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2,709 results on '"J. Bard"'

1. High-Resolution Transcriptomic Landscape of the Human Submandibular Gland

Author

E. Horeth, J. Bard, M. Che, T. Wrynn, E.A.C. Song, B. Marzullo, M.S. Burke, S. Popat, T. Loree, J. Zemer, J.L. Tapia, J. Frustino, J.M. Kramer, S. Sinha, and R.A. Romano

Subjects
General Dentistry
Abstract

Saliva-secreting and transporting cells are part of the complex cellular milieu of the human salivary gland, where they play important roles in normal glandular physiology and diseased states. However, comprehensive molecular characterization, particularly at single-cell resolution, is still incomplete, in part due to difficulty in procuring normal human tissues. Here, we perform an in-depth analysis of male and female adult human submandibular gland (SMG) samples by bulk RNA sequencing (RNA-seq) and examine the molecular underpinnings of the heterogeneous cell populations by single-cell (sc) RNA-seq. Our results from scRNA-seq highlight the remarkable diversity of clusters of epithelial and nonepithelial cells that reside in the SMG that is also faithfully recapitulated by deconvolution of the bulk-RNA data sets. Our analyses reveal complex transcriptomic heterogeneity within both the ductal and acinar subpopulations and identify atypical SMG cell types, such as mucoacinar cells that are unique to humans and ionocytes that have been recently described in the mouse. We use CellChat to explore ligand–receptor interactome predictions that likely mediate crucial cell–cell communications between the various cell clusters. Finally, we apply a trajectory inference method to investigate specific cellular branching points and topology that offers insights into the dynamic and complex differentiation process of the adult SMG. The data sets and the analyses herein comprise an extensive wealth of high-resolution information and a valuable resource for a deeper mechanistic understanding of human SMG biology and pathophysiology.

Published
2023
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2. Diffusion at the interface of laser welded polyamide-6.6 and aluminum assemblies

Author

P. Hirchenhahn, A. Al-Sayyad, J. Bardon, P. Plapper, and L. Houssiau

Subjects
Diffusion, Interface, Laser welding, ToF-SIMS, Information entropy, Mining engineering. Metallurgy, TN1-997
Abstract

Polymer/metal assemblies are widely used in industry, especially the automotive industry, to get more cost efficient and light weight structures. Although they present many advantages, their assembly remains challenging. Laser welding is an effective solution. Indeed, it is fast, presents high design freedom, and does not require any interstitial material. Furthermore, surface pretreatment can tune mechanical resistance. However, the root causes of adhesion remain partly unknown. The existence of chemical bonding at the interface has already been established, but other adhesion phenomena, such as diffusion, remain to be investigated. The aim of this study is to investigate the existence of diffusion at the interface between the polymer and the metal after laser welding. Therefore, a common material combination was used: polyamide-6.6 and aluminum. A thin film of polyamide-6.6 was deposited on mirror-polished aluminum, and two depth profiles out and in the weld were acquired by ToF-SIMS and compared. The results show that the diffusion of aluminum occurs at the interface of polyamide-6.6, with a diffusion length of approximately 22 nm.

Published
2024
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7. Surface Interrogation of Electrodeposited MnO x and CaMnO 3 Perovskites by Scanning Electrochemical Microscopy: Probing Active Sites and Kinetics for the Oxygen Evolution Reaction

Author

Zhaoyu Jin and Allen J. Bard

Subjects
Materials science, 010405 organic chemistry, Inorganic chemistry, Oxygen evolution, chemistry.chemical_element, General Medicine, General Chemistry, Manganese, 010402 general chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, Amorphous solid, Reaction rate, Scanning electrochemical microscopy, chemistry, Oxidation state, Titration, Perovskite (structure)
Abstract

Surface interrogation scanning electrochemical microscopy (SI-SECM) of two electrodeposited manganese-based electrocatalysts, amorphous MnOx and perovskite CaMnO3 , was used to investigate the manganese oxidation state relating to the oxygen evolution reaction (OER) under neutral conditions. The results indicate the amounts of MnIII and MnIV species in MnOx and CaMnO3 depend on potential. A MnV species was identified in both structures during the OER. Time-delay titration of MnV further revealed that MnOx produced two types of active sites with different OER reaction rates: k'fast (MnOx )=1.21 s-1 and k'slow (MnOx )=0.24 s-1 . In contrast, CaMnO3 perovskites in which the MnV species formed at a less positive potential than that in MnOx , displayed only one kinetic behavior with a faster reaction rate of 1.72 s-1 .

Published
2020
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9. Doping of the Semiconducting Polymer Poly(3-hexylthiophene) (P3HT) in Organic Photoelectrochemical Cells

Author

Won Tae Choi and Allen J. Bard

Subjects
Materials science, Dopant, Doping, 02 engineering and technology, Photoelectrochemical cell, 010402 general chemistry, 021001 nanoscience & nanotechnology, Semiconducting polymer, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Organic semiconductor, General Energy, Chemical engineering, Physical and Theoretical Chemistry, Cyclic voltammetry, 0210 nano-technology
Abstract

We demonstrate the dependence of photoelectrochemical properties of the organic semiconductor film poly(3-hexylthiophene) (P3HT) on the dopant species. We use cyclic voltammetry to characterize ele...

Published
2020
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10. Lipid Membrane Permeability of Synthetic Redox DMPC Liposomes Investigated by Single Electrochemical Collisions

Author

Allen J. Bard, Estelle Lebègue, Frédéric Barrière, Chimie Et Interdisciplinarité : Synthèse, Analyse, Modélisation (CEISAM), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), University of Texas at Austin [Austin], CHE-1405248, Division of Chemistry, F-0021, Welch Foundation, Université de Nantes (UN)-Université de Nantes (UN)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Liposome, Chemistry, 010401 analytical chemistry, technology, industry, and agriculture, chemistry.chemical_element, Electrochemical detection, 010402 general chemistry, Electrochemistry, 01 natural sciences, Redox, 0104 chemical sciences, Analytical Chemistry, Chemical engineering, Permeability (electromagnetism), [CHIM]Chemical Sciences, lipids (amino acids, peptides, and proteins), Lipid bilayer, Carbon
Abstract

International audience; The electrochemical detection of synthetic redox DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) liposomes by single collisions at 10 μm diameter carbon and Pt ultramicroelectrodes (UMEs) is reported. To study the parameters influencing the lipid membrane opening/permeability, the electrochemical detection of single redox DMPC liposome collisions at polarized UMEs was investigated under different experimental conditions (addition of surfactant, temperature). The electrochemical responses recorded showed that the permeability of the DMPC lipid membrane (tuned by addition of Triton X-100 surfactant or by the increase of the solution temperature) is a key parameter for the liposome membrane electroporation process and hence for the release and oxidation of its redox content during the collision onto UMEs. The presence of ferrocenemethanol as an additional redox probe in the aqueous solution (at room temperature and without addition of surfactant) is also an interesting strategy to detect current spikes corresponding to single redox DMPC liposome collisions with KFe(CN)/KFe(CN) as the encapsulated aqueous redox probe.

Published
2020
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12. Spectrum of MRI findings in central nervous system affection in Lyme neuroborreliosis

Author

T. Volk, H. Urbach, V. Fingerle, J. Bardutzky, S. Rauer, and Rick Dersch

Subjects
Lyme disease, Lyme neuroborreliosis, Cerebral MRI imaging, CSF, Neuroinfectious diseases, Encephalitis, Medicine, Science
Abstract

Abstract Affections of the central nervous system (CNS) rarely occur in Lyme neuroborreliosis (LNB). CNS manifestations can have residual neurological symptoms despite antibiotic treatment. We explored the spectrum of CNS affections in patients with LNB in a tertiary care center in a region endemic for Lyme borreliosis. We retrospectively included patients treated at a tertiary care center from January 2020–December 2021 fulfilling the case criteria for LNB as stated in the current German guideline on LNB. Clinical data, cerebrospinal fluid (CSF) findings and MRI imaging were collected. We included 35 patients with LNB, 24 with early manifestations and 11 with CNS-LNB. CNS-LNB patients had encephalomyelitis (n = 6) or cerebral vasculitis (n = 5). Patients with early LNB and CNS-LNB differed regarding albumin CSF/serum quotient and total protein in CSF. Duration from onset of symptoms until diagnosis was statistically significantly longer in patients with encephalomyelitis. MRI findings were heterogeneous and showed longitudinal extensive myelitis, perimedullar leptomeningeal enhancement, pontomesencephalic lesions or cerebral vasculitis. CNS-LNB can present with a variety of clinical syndromes and MRI changes. No clear pattern of MRI findings in CNS-LNB could be identified. The role of MRI consists in ruling out other causes of neurological symptoms.

Published
2024
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13. Electrodeposition of crystalline silicon films from silicon dioxide for low-cost photovoltaic applications

Author

Donald R. Sadoway, Xingli Zou, Jianbang Ge, Allen J. Bard, Edward T. Yu, and Li Ji

Subjects
Solar cells, Materials science, Silicon, Silicon dioxide, Science, General Physics and Astronomy, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, 7. Clean energy, General Biochemistry, Genetics and Molecular Biology, Article, law.invention, chemistry.chemical_compound, law, Photovoltaics, Solar cell, Wafer, Crystalline silicon, lcsh:Science, Multidisciplinary, business.industry, Doping, Photovoltaic system, General Chemistry, 021001 nanoscience & nanotechnology, Electrical and electronic engineering, 0104 chemical sciences, chemistry, Optoelectronics, lcsh:Q, 0210 nano-technology, business, Materials for energy and catalysis
Abstract

Crystalline-silicon solar cells have dominated the photovoltaics market for the past several decades. One of the long standing challenges is the large contribution of silicon wafer cost to the overall module cost. Here, we demonstrate a simple process for making high-purity solar-grade silicon films directly from silicon dioxide via a one-step electrodeposition process in molten salt for possible photovoltaic applications. High-purity silicon films can be deposited with tunable film thickness and doping type by varying the electrodeposition conditions. These electrodeposited silicon films show about 40 to 50% of photocurrent density of a commercial silicon wafer by photoelectrochemical measurements and the highest power conversion efficiency is 3.1% as a solar cell. Compared to the conventional manufacturing process for solar grade silicon wafer production, this approach greatly reduces the capital cost and energy consumption, providing a promising strategy for low-cost silicon solar cells production., The photovoltaics market has been dominated by crystalline silicon solar cells despite the high cost of the silicon wafers. Here Zou et al. develop a one-step electrodeposition process in molten salt to produce high-purity solar-grade silicon films, delivering power conversion efficiency of 3.1%.

Published
2019

14. Electrochemical Production of Si without Generation of CO 2 Based on the Use of a Dimensionally Stable Anode in Molten CaCl 2

Author

Allen J. Bard, Brian P. Chaplin, Soroush Almassi, Li Ji, Xingli Zou, and Jianbang Ge

Subjects
Photocurrent, Materials science, 010405 organic chemistry, Photoelectrochemistry, Oxygen evolution, General Chemistry, General Medicine, 010402 general chemistry, Electrochemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, Anode, Cathodic protection, Chemical engineering, Wafer, Layer (electronics)
Abstract

The current Si production process is based on the high-temperature (1700 °C) reduction of SiO2 with carbon that produces large amounts of CO2 . We report an alternative low-temperature (850 °C) process based on the reduction of SiO2 in molten CaCl2 that does not produce CO2 . It utilizes an anode material (Ti4 O7 ) capable of sustained oxygen evolution. Two types of this anode material, dense Ti4 O7 and porous Ti4 O7 , were tested. The dense anode showed a better performance. The anode stability is attributed to the formation of a protective TiO2 layer on its surface. In situ periodic current reversal and ex situ H2 reduction could be used for extending the lifetime of the anodes. The findings show that this material can be applied as a recyclable anode in molten CaCl2 . Si wires, films, and particles were deposited with this anode under different cathodic current densities. The prepared Si film exhibited ≈30-40 % of the photocurrent response of a commercial p-type Si wafer, indicating potential use in photovoltaic cells.

Published
2019
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15. Probing Size and Substrate Effects on the Hydrogen Evolution Reaction by Single Isolated Pt Atoms, Atomic Clusters, and Nanoparticles

Author

Min Zhou, Shujuan Bao, and Allen J. Bard

Subjects
Surface Properties, Chemistry, Analytical chemistry, Metal Nanoparticles, Nanoparticle, Substrate (chemistry), Electrochemical Techniques, General Chemistry, 010402 general chemistry, Electrochemistry, 01 natural sciences, Biochemistry, Catalysis, 0104 chemical sciences, Kinetics, Colloid and Surface Chemistry, Electrode, Atom, Cluster (physics), Particle size, Particle Size, Microelectrodes, Hydrogen, Platinum
Abstract

We report the catalytic activity of a single, isolated Pt deposit on Bi and Pb supports to probe the size and substrate effects on the electrochemical hydrogen evolution reaction (HER). Deposits were made electrolytically by an atom-by-atom method in a controlled plating; we prepared an individual Pt deposit on Bi and Pb ultramicroelectrodes (UMEs) such as a single isolated atom, clusters containing one to five Pt atoms, and nanoparticles to about 10 nm radius. A steady-state voltammogram on the single Pt deposits is observed by electrocatalytic amplification of the HER, with a negligible contribution by the HER at the substrate UME. A single Pt atom can act as an electrode for the HER, showing a diffusion-limiting current plateau in the voltammogram that can be used to estimate the radius of a single deposit. We simulated the voltammograms of the individual deposits, assuming the Volmer step of the HER is appropriate for a Pt cluster deposit, to obtain kinetic parameters for each deposit. The HER kinetics increases as the particle radius increases from ∼0.2 to ∼4 nm for Bi and Pb substrates and then reaches a limiting plateau. The limiting kinetics on the Bi substrate approaches that of bulk Pt while that on the Pb substrate is much smaller.

Published
2019
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16. The 2018 rift eruption and summit collapse of Kīlauea Volcano

Author

G. Fisher, Kyle R. Anderson, C. J. Moniz, R. L. Lee, Matthew K. Burgess, M. Cappos, Bruce F. Houghton, W. Tollett, Asta Miklius, Loren Antolik, J. L. Ball, S. Fuke, J. Bard, Carolyn Parcheta, Christina A. Neal, Donald A. Swanson, Matthew R. Patrick, K. Mulliken, Frank A. Trusdell, K. Calles, J. L. Babb, P. Dotray, Patricia A. Nadeau, Jefferson C. Chang, Liliana G. DeSmither, James P. Kauahikaua, Tamar Elias, Laura E. Clor, Paul Lundgren, Michael P. Poland, Hannah R. Dietterich, David E. Damby, A. K. Diefenbach, R. Hazlett, A. H. Lerner, Peter F. Cervelli, P. Fukunaga, C. A. Gansecki, W. Million, Michelle L. Coombs, Ingrid A. Johanson, Cynthia Werner, Christoph Kern, Tim R. Orr, Gregory P. Waite, Michael H. Zoeller, Kevan Kamibayashi, Paul G. Okubo, Peter J. Kelly, B. Shiro, S. Conway, S. R. Brantley, E. K. Montgomery-Brown, Weston A. Thelen, S. Pekalib, and E. F. Younger

Subjects
geography, Multidisciplinary, Summit, geography.geographical_feature_category, Rift, 010504 meteorology & atmospheric sciences, Lava, 010502 geochemistry & geophysics, 01 natural sciences, Volcano, Magma, medicine, Caldera, medicine.symptom, Rift zone, Geology, Seismology, Collapse (medical), 0105 earth and related environmental sciences
Abstract

Connecting caldera collapse The Kīlauea Volcano on the island of Hawai‘i erupted for 3 months in 2018. Neal et al. present a summary of the eruption sequence along with a variety of geophysical observations collected by the Hawaiian Volcano Observatory. The cyclic inflation, deflation, and eventual collapse of the summit was tied to lava eruption from lower East Rift Zone fissures. A total volume of 0.8 cubic kilometers of magma erupted, roughly the equivalent of 320,000 swimming pools, which matched the change in volume at the summit. Science , this issue p. 367

Published
2019
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18. sj-pdf-1-jdr-10.1177_00220345211012000 – Supplemental material for A Global Vista of the Epigenomic State of the Mouse Submandibular Gland

Author

C. Gluck, S. Min, A. Oyelakin, M. Che, E. Horeth, E.A.C. Song, J. Bard, N. Lamb, S. Sinha, and R.A. Romano

Subjects
110599 Dentistry not elsewhere classified, FOS: Materials engineering, FOS: Clinical medicine, 91299 Materials Engineering not elsewhere classified
Abstract

Supplemental material, sj-pdf-1-jdr-10.1177_00220345211012000 for A Global Vista of the Epigenomic State of the Mouse Submandibular Gland by C. Gluck, S. Min, A. Oyelakin, M. Che, E. Horeth, E.A.C. Song, J. Bard, N. Lamb, S. Sinha and R.A. Romano in Journal of Dental Research

Published
2021
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19. Atom-by-atom electrodeposition of single isolated cobalt oxide molecules and clusters for studying the oxygen evolution reaction

Author

Allen J. Bard and Zhaoyu Jin

Subjects
inorganic chemicals, Multidisciplinary, Materials science, Inorganic chemistry, Limiting current, Oxygen evolution, chemistry.chemical_element, Electrochemistry, Electrocatalyst, Catalysis, chemistry.chemical_compound, chemistry, Physical Sciences, Hydroxide, Cobalt, Cobalt oxide
Abstract

We report an electrodeposition protocol for preparing isolated cobalt oxide single molecules (Co(1)O(x)) and clusters (Co(n)O(y)) on a carbon fiber nanoelectrode. The as-prepared deposits are able to produce well-defined steady-state voltammograms for the oxygen evolution reaction (OER) in alkaline media, where the equivalent radius (r(d)) is estimated by the limiting current of hydroxide oxidation in accordance with the electrocatalytic amplification model. The size of isolated clusters obtained from the femtomolar Co(2+) solution through an atom-by-atom technique can reach as small as 0.21 nm (r(d)) which is approximately the length of Co–O bond in cobalt oxide. Therefore, the deposit was close to that of a Co(1)O(x) single molecule with only one cobalt ion, the minimum unit of the cobalt-based oxygen-evolving catalyst. Additionally, the size-dependent catalysis of the OER on Co(n)O(y) deposits shows a faster relative rate on the smaller cluster in terms of the potential at a given current density, implying the single molecular catalyst shows a superior OER activity.

Published
2020

20. Measurements of the Absolute Branching Fractions of B± →k±Xc c

Author

A. J. Edwards, F. Simonetto, W. F. Mader, R. H. Schindler, Fry, Shanhui Fan, I Eschrich, W. Menges, M Bruinsma, K. Suzuki, T Schalk, R. Kroeger, J. M. Bauer, D. Boutigny, H. Nicholson, A Petzold, Marcello Rotondo, AT Watson, Martino Margoni, H. U. Flaecher, L. M. Cremaldi, M. Verderi, A Pompili, T. Hadig, U. Mallik, S. K. Swain, KS Chaisanguanthum, Muller, J. F. Strube, Roberto Calabrese, AN Yushkov, E. Gabathuler, Jordan Nash, O. Hamon, R. R. Kofler, M. Krishnamurthy, C. M. Cormack, AE Blinov, WH Toki, R Schwierz, Heiko Lacker, M Battaglia, D. G. Hitlin, S. Ye, M Andreotti, T. C. Petersen, Corrado Angelini, W. Gradl, Stephen Sekula, G Mancinelli, F. C. Porter, R. Ter-Antonyan, R. C. Field, D. E. Wagoner, W. O. Ruddick, Gabriele Simi, A. Buzzo, A. K. Mohapatra, D. J. Payne, J Kadyk, L Piemontese, F. Bucci, P. Wang, ML Vetere, G Lynch, D. Côté, L. Gioi, TW Beck, P. S. Jackson, R. Godang, D. Piccolo, Tisserand, G. Therin, J Marks, W. Bhimji, Gill, Q Zeng, S. Rodier, Nicola Neri, F. Lodovico, O. L. Buchmueller, D. Su, Nicolo De Groot, Wp Vazquez, B. Cheng, Chunhui Chen, K. R. Schubert, C. L. Davis, R. Gamet, H. L. Lynch, A. Gaidot, G. P. Gopal, B. Viaud, Maurizio Pierini, M. P. Kelly, M Saleem, D. J. Bard, A. Calcaterra, J. Ocariz, R Nogowski, M. Piccolo, M. T. Allen, S. Saremi, M Mandelkern, A. W. Weidemann, Matteo Rama, D. M. Strom, Mauro Morandin, G Brandenburg, S. Playfer, C. Bozzi, M. Haire, J. C. Williams, Halyo, K. Honscheid, C. A. Chavez, C. L. Edgar, J Zhang, LT Kerth, D. Dong, DC Williams, JE Sundermann, SE Morgan, J. M. Roney, JS Minamora, Luca Lista, S. J. Gowdy, K. A. George, J. G. Smith, M. B. Nikolich, D Kirkby, C. Cartaro, A. Oyanguren, G. Batignani, R. Sacco, C. Roat, M. Benayoun, Fabio Cossutti, M. A. Mazzoni, G. Wormser, RJ Wilson, H. L. Snoek, S Curry, J. W. Gary, K. Goetzen, B. Franek, P Bloom, R. Frey, H. J. Bulten, CJ Flacco, A. M. Eisner, D. W. G. S. Leith, Nicolas Berger, D. A. Hopkins, S. M. Spanier, Vladimir Blinov, G Vasileiadis, B Lewandowski, J Kroseberg, C. Gatto, A Santroni, S Tosi, C. K. Lae, D. B. MacFarlane, R. J. Barlow, G. Rizzo, E. P. Solodov, D Altenburg, W. N. Cottingham, N. Chevalier, M. Posocco, Marco Bomben, R. Barate, D. Bernard, JD Richman, C Thiebaux, J.J. Reidy, R. Bula, T. Cuhadar-Donszelmann, T. Schroeder, Johnson, G. Schott, M. H. Kelsey, T. Abe, J. Stelzer, C. Touramanis, J. P. Burke, E. Torrence, Giuseppe Della Ricca, Sw. Banerjee, M Pappagallo, Abner Soffer, C. Hearty, R. Claus, S. Prell, Matteo Negrini, Thomas Allmendinger, C. Dallapiccola, J. J. Hollar, Y. P. Lau, D. Fortin, J. A. McKenna, Kyung-Soo Yi, G. Calderini, Douglas Wright, P Lund, James H Cochran, R. Cenci, T. Glanzman, R. L. Flack, HP Paar, J. L. Ritchie, EA Eckhart, S. Bettarini, A. J.S. Smith, Philippe Grenier, M Macri, J. M. LoSecco, E Feltresi, A. Zallo, J. Libby, AB Breon, FS Tehrani, G. Grosdidier, I. J. Forster, D. J. Summers, M. Spitznagel, B Stugu, S. F. Ganzhur, H. R. Band, B Spaan, H. B. Crawley, I. Kitayama, S. I. Serednyakov, MG Wilson, M Morii, KE Ford, D Best, Yuri Skovpen, R. J. Sobie, G. W. London, Y Groysman, J. C. Dingfelder, N. B. Sinev, BL Hartfiel, R. Liu, Daniele Del Re, Luth, A. Perazzo, C. Voena, L. Vitale, W. R. Innes, RG Jacobsen, E Chen, Alam, T. S. Mattison, D. A. Sanders, F. Martinez-Vidal, J. Chauveau, M. J.J. John, R. Aleksan, S. B. Zain, G. P. Dubois-Felsmann, H. A. Neal, S. Willocq, D. Monorchio, I Ofte, K Peters, T. B. Moore, Q. K. Wong, B. T. Meadows, J. Biesiada, A Samuel, V. B. Koptchev, V. E. Ozcan, S. A. Majewski, A Seiden, P. Tan, C. Hast, D. J. Lange, G. Piredda, A. Dvoretskii, W. Kozanecki, M. Legendre, GS Abrams, G. Raven, T. Held, C. Lu, D. Judd, Y. B. Pan, D. Bettoni, M. Lu, Dmytro Kovalskyi, J. I. Yi, C. M. Brown, Y Xie, H. W. Zhao, P. D. Dauncey, J. P. Lees, R. Kowalewski, A. Hocker, S. Ahmed, D. Gamba, A. Lusiani, F. Gallo, RK Mommsen, P. R. Burchat, S Schrenk, M. Pioppi, F. Polci, N. S. Knecht, V. P. Druzhinin, Y Karyotakis, W. J. Wisniewski, A. Stocchi, F. R. Wappler, CM Hawkes, F. Forti, P. C. Kim, A. Lazzaro, J. E. Brau, Tim Adye, X. Giroux, M. Carpinelli, M. T. Naisbit, Lydia Roos, M. Morganti, C. Voci, Eleonora Luppi, R. Baldini-Ferroli, J. Schwiening, Julie Malcles, R. D. Kass, Q. H. Guo, C. De La Vaissiere, H. Kagan, H. Schröder, R. J. Parry, D. Dujmic, Tetiana Hrynova, K. K. Gan, D. A. Roberts, Anders Ryd, N. D. Qi, J. M. Thompson, C. Yeche, A. D'Orazio, F. E. Taylor, A Chen, T. M. Hong, MA Mazur, BA Schumm, D. Aston, C Campagnari, GH de Monchenault, M. H. Schune, Guglielmo De Nardo, G. Marchiori, U. Uwer, BC Shen, J Wu, M. Zito, NA Roe, C. P. O'Grady, M Dickopp, W. Dunwoodie, PJ Clark, M. A. Baak, M Chao, A. V. Telnov, WT Ford, J. Olsen, E. O. Olaiya, M. A. Saeed, W. T. Meyer, Y. S. Zhu, A. Mihalyi, Eyges, R. Stroili, J Schubert, Wagner, Hyunyong Kim, Maurizio Biasini, N. R. Barlow, Pierluigi Paolucci, U Nauenberg, Kenji Hamano, T.R. McMahon, C Buchanan, TJ Harrison, Ulrik Egede, Matthew J. Graham, M. Fritsch, T Piatenko, F Couderc, RW Kadel, S. S. Hertzbach, N. Danielson, R. Messner, A Zghiche, R. Faccini, Sokoloff, F. Ferrarotto, A. J. Lankford, Marcella Bona, AD Bukin, C. Patrignani, A. Cunha, F. Palombo, D Brown, E. Paoloni, F. Salvatore, JF Hirschauer, EJ Hill, S. Pacetti, Owen Rosser Long, G. B. Mohanty, L. Wilden, A. Kreisel, Kefeng Wang, F. Galeazzi, R. Cowan, Gabriele Benelli, P. Taras, Lepeltier, R. F. Schwitters, Mohamed H. Ahmed, M. L. Kocian, P. Roudeau, P. D. Jackson, AJ Hart, A. P. Onuchin, R. K. Yamamoto, J. J. Back, G. Finocchiaro, L Zhang, H. Staengle, PJ Oddone, W Verkerke, J Brose, LM Mir, E. Grauges, X. R. Chen, S. Brunet, M. G. Green, Adrian John Bevan, R. Bartoldus, P Kyberd, Zongfu Yu, G. A. Cowan, M. Gaspero, J. P. Coleman, G. Eigen, M Bondioli, C. T. Potter, A. Snyder, Mario Giorgi, Monge, Michael Steinke, S. Morganti, L. Gladney, M. J. Charles, R. Eckmann, F. F. Wilson, L. Bosisio, S Otto, Sridhara Dasu, M. Davier, G Kukartsev, W Roethel, Karsten Koeneke, K. A. Ulmer, Francesco Fabozzi, G. R. Bonneaud, A. J.R. Weinstein, Colin Jessop, Mousumi Datta, R. Prepost, Andrei Gritsan, I Narsky, SD Foulkes, HK Hadavand, Azzolini, A. Khan, F. Bellini, T. Orimoto, M Barrett, A. Olivas, M. Weaver, G. Vasseur, K. T. Flood, M. L. Perl, J. T. Boyd, Joseph Izen, K. C. Schofield, A. Roodman, R Andreassen, T. Pulliam, S Rahatlou, J. A. Ernst, H. Briand, Roland Waldi, F. Ferroni, N. Cavallo, L. Lanceri, Stéphane Plaszczynski, D. A. Bowerman, Paul Fraser Harrison, P. M. Patel, S. J. Chen, J.H. Panetta, X. Chai, M. K. Sullivan, A. Jawahery, Y. G. Kolomensky, Gabriella Sciolla, W. M. Bugg, G. Cibinetto, B. N. Ratcliff, Emanuele Di Marco, RN Cahn, P Spradlin, Eschenburg, B. A. Petersen, J. Dorfan, A. M. Boyarski, C. L. Brown, JW Berryhill, MT Ronan, P. E. Kutter, P. K. Behera, Ph Leruste, F Muheim, G.J. Wagner, N. Arnaud, B. Mayer, A. K. Yarritu, Convery, I. M. Peruzzi, C. H. Cheng, Luigi Del Buono, B. Aubert, E Robutti, H. Marsiske, R. de Sangro, S. L. Wu, RS Dubitzky, F. Bianchi, A. E. Rubin, N. van Bakel, C. C. Young, F. Diberder, J. Allison, WA Wenzel, A. M. Lutz, Poireau, Hui Li, G. Rong, Sergio Grancagnolo, R Contri, S. Passaggio, R. S. Panvini, M Pelizaeus, Wilson, W. D. Hulsbergen, Xingguo Li, M. V. Purohit, J. Albert, Bruce Mellado, Klose, M. Wittgen, E Charles, Pieter David, Ziegler, V. B. Golubev, Roberto Covarelli, A. Palano, G. Cavoto, David Hutchcroft, Bryan Dahmes, S. Luitz, S Schenk, J. Va’vra, Sharma, D. Hufnagel, Peter Elmer, DP Stoker, E Won, A. M. Eichenbaum, S. Ricciardi, L Teodorescu, C. A. Heusch, E. A. Kravchenko, Crisostomo Sciacca, CT Day, J. C. Chen, P. Patteri, R Capra, D. Wright, B. Bhuyan, B. G. Fulsom, X. C. Lou, J. J. Walsh, A. M. Rahimi, T. E. Latham, D. N. Brown, Gaillard, G. D. Lafferty, T Brandt, M Pripstein, Markus Cristinziani, O. Igonkina, F. X. Yumiceva, J Button-Shafer, S. H. Robertson, G Nesom, S. Emery, G. Blaylock, Herbert Koch, A Hauke, Lombardo, F. Blanc, A. Satpathy, M. C. Hodgkinson, G. Graziani, E. I. Rosenberg, W. S. Lockman, A. A. Salnikov, M. C. Simani, F. Anulli, S. Dittongo, U Langenegger, Lees J.P., Poireau V., Tisserand V., Grauges E., Palano A., Eigen G., Brown D.N., Kolomensky Y.G., Fritsch M., Koch H., Schroeder T., Cheaib R., Hearty C., Mattison T.S., McKenna J.A., So R.Y., Blinov V.E., Buzykaev A.R., Druzhinin V.P., Golubev V.B., Kozyrev E.A., Kravchenko E.A., Onuchin A.P., Serednyakov S.I., Skovpen Y.I., Solodov E.P., Todyshev K.Y., Lankford A.J., Dey B., Gary J.W., Long O., Eisner A.M., Lockman W.S., Panduro Vazquez W., Chao D.S., Cheng C.H., Echenard B., Flood K.T., Hitlin D.G., Kim J., Li Y., Miyashita T.S., Ongmongkolkul P., Porter F.C., Rohrken M., Huard Z., Meadows B.T., Pushpawela B.G., Sokoloff M.D., Sun L., Smith J.G., Wagner S.R., Bernard D., Verderi M., Bettoni D., Bozzi C., Calabrese R., Cibinetto G., Fioravanti E., Garzia I., Luppi E., Santoro V., Calcaterra A., De Sangro R., Finocchiaro G., Martellotti S., Patteri P., Peruzzi I.M., Piccolo M., Rotondo M., Zallo A., Passaggio S., Patrignani C., Shuve B.J., Lacker H.M., Bhuyan B., Mallik U., Chen C., Cochran J., Prell S., Gritsan A.V., Arnaud N., Davier M., Le Diberder F., Lutz A.M., Wormser G., Lange D.J., Wright D.M., Coleman J.P., Gabathuler E., Hutchcroft D.E., Payne D.J., Touramanis C., Bevan A.J., Di Lodovico F., Sacco R., Cowan G., Banerjee S., Davis C.L., Denig A.G., Gradl W., Griessinger K., Hafner A., Schubert K.R., Barlow R.J., Lafferty G.D., Cenci R., Jawahery A., Roberts D.A., Cowan R., Robertson S.H., Seddon R.M., Neri N., Palombo F., Cremaldi L., Godang R., Summers D.J., Taras P., De Nardo G., Sciacca C., Raven G., Jessop C.P., Losecco J.M., Honscheid K., Kass R., Gaz A., Margoni M., Posocco M., Simi G., Simonetto F., Stroili R., Akar S., Ben-Haim E., Bomben M., Bonneaud G.R., Calderini G., Chauveau J., Marchiori G., Ocariz J., Biasini M., Manoni E., Rossi A., Batignani G., Bettarini S., Carpinelli M., Casarosa G., Chrzaszcz M., Forti F., Giorgi M.A., Lusiani A., Oberhof B., Paoloni E., Rama M., Rizzo G., Walsh J.J., Zani L., Smith A.J.S., Anulli F., Faccini R., Ferrarotto F., Ferroni F., Pilloni A., Piredda G., Bunger C., Dittrich S., Grunberg O., Hess M., Leddig T., Voss C., Waldi R., Adye T., Wilson F.F., Emery S., Vasseur G., Aston D., Cartaro C., Convery M.R., Dorfan J., Dunwoodie W., Ebert M., Field R.C., Fulsom B.G., Graham M.T., Hast C., Innes W.R., Kim P., Leith D.W.G.S., Luitz S., Macfarlane D.B., Muller D.R., Neal H., Ratcliff B.N., Roodman A., Sullivan M.K., Va'Vra J., Wisniewski W.J., Purohit M.V., Wilson J.R., Randle-Conde A., Sekula S.J., Ahmed H., Bellis M., Burchat P.R., Puccio E.M.T., Alam M.S., Ernst J.A., Gorodeisky R., Guttman N., Peimer D.R., Soffer A., Spanier S.M., Ritchie J.L., Schwitters R.F., Izen J.M., Lou X.C., Bianchi F., De Mori F., Filippi A., Gamba D., Lanceri L., Vitale L., Martinez-Vidal F., Oyanguren A., Albert J., Beaulieu A., Bernlochner F.U., King G.J., Kowalewski R., Lueck T., Nugent I.M., Roney J.M., Sobie R.J., Tasneem N., Gershon T.J., Harrison P.F., Latham T.E., Prepost R., Wu S.L., Lees, J. P., Poireau, V., Tisserand, V., Grauges, E., Palano, A., Eigen, G., Brown, D. N., Kolomensky, Y. G., Fritsch, M., Koch, H., Schroeder, T., Cheaib, R., Hearty, C., Mattison, T. S., Mckenna, J. A., So, R. Y., Blinov, V. E., Buzykaev, A. R., Druzhinin, V. P., Golubev, V. B., Kozyrev, E. A., Kravchenko, E. A., Onuchin, A. P., Serednyakov, S. I., Skovpen, Y. I., Solodov, E. P., Todyshev, K. Y., Lankford, A. J., Dey, B., Gary, J. W., Long, O., Eisner, A. M., Lockman, W. S., Panduro Vazquez, W., Chao, D. S., Cheng, C. H., Echenard, B., Flood, K. T., Hitlin, D. G., Kim, J., Li, Y., Miyashita, T. S., Ongmongkolkul, P., Porter, F. C., Rohrken, M., Huard, Z., Meadows, B. T., Pushpawela, B. G., Sokoloff, M. D., Sun, L., Smith, J. G., Wagner, S. R., Bernard, D., Verderi, M., Bettoni, D., Bozzi, C., Calabrese, R., Cibinetto, G., Fioravanti, E., Garzia, I., Luppi, E., Santoro, V., Calcaterra, A., De Sangro, R., Finocchiaro, G., Martellotti, S., Patteri, P., Peruzzi, I. M., Piccolo, M., Rotondo, M., Zallo, A., Passaggio, S., Patrignani, C., Shuve, B. J., Lacker, H. M., Bhuyan, B., Mallik, U., Chen, C., Cochran, J., Prell, S., Gritsan, A. V., Arnaud, N., Davier, M., Le Diberder, F., Lutz, A. M., Wormser, G., Lange, D. J., Wright, D. M., Coleman, J. P., Gabathuler, E., Hutchcroft, D. E., Payne, D. J., Touramanis, C., Bevan, A. J., Di Lodovico, F., Sacco, R., Cowan, G., Banerjee, S., Davis, C. L., Denig, A. G., Gradl, W., Griessinger, K., Hafner, A., Schubert, K. R., Barlow, R. J., Lafferty, G. D., Cenci, R., Jawahery, A., Roberts, D. A., Cowan, R., Robertson, S. H., Seddon, R. M., Neri, N., Palombo, F., Cremaldi, L., Godang, R., Summers, D. J., Taras, P., De Nardo, G., Sciacca, C., Raven, G., Jessop, C. P., Losecco, J. M., Honscheid, K., Kass, R., Gaz, A., Margoni, M., Posocco, M., Simi, G., Simonetto, F., Stroili, R., Akar, S., Ben-Haim, E., Bomben, M., Bonneaud, G. R., Calderini, G., Chauveau, J., Marchiori, G., Ocariz, J., Biasini, M., Manoni, E., Rossi, A., Batignani, G., Bettarini, S., Carpinelli, M., Casarosa, G., Chrzaszcz, M., Forti, F., Giorgi, M. A., Lusiani, A., Oberhof, B., Paoloni, E., Rama, M., Rizzo, G., Walsh, J. J., Zani, L., Smith, A. J. S., Anulli, F., Faccini, R., Ferrarotto, F., Ferroni, F., Pilloni, A., Piredda, G., Bunger, C., Dittrich, S., Grunberg, O., Hess, M., Leddig, T., Voss, C., Waldi, R., Adye, T., Wilson, F. F., Emery, S., Vasseur, G., Aston, D., Cartaro, C., Convery, M. R., Dorfan, J., Dunwoodie, W., Ebert, M., Field, R. C., Fulsom, B. G., Graham, M. T., Hast, C., Innes, W. R., Kim, P., Leith, D. W. G. S., Luitz, S., Macfarlane, D. B., Muller, D. R., Neal, H., Ratcliff, B. N., Roodman, A., Sullivan, M. K., Va'Vra, J., Wisniewski, W. J., Purohit, M. V., Wilson, J. R., Randle-Conde, A., Sekula, S. J., Ahmed, H., Bellis, M., Burchat, P. R., Puccio, E. M. T., Alam, M. S., Ernst, J. A., Gorodeisky, R., Guttman, N., Peimer, D. R., Soffer, A., Spanier, S. M., Ritchie, J. L., Schwitters, R. F., Izen, J. M., Lou, X. C., Bianchi, F., De Mori, F., Filippi, A., Gamba, D., Lanceri, L., Vitale, L., Martinez-Vidal, F., Oyanguren, A., Albert, J., Beaulieu, A., Bernlochner, F. U., King, G. J., Kowalewski, R., Lueck, T., Nugent, I. M., Roney, J. M., Sobie, R. J., Tasneem, N., Gershon, T. J., Harrison, P. F., Latham, T. E., Prepost, R., and Wu, S. L.

Subjects
Physics, Particle physics, Kjerne- og elementærpartikkelfysikk: 431 [VDP], Meson, 010308 nuclear & particles physics, Electron–positron annihilation, General Physics and Astronomy, BaBar experiment, Bottom meson, BaBar, PEP-II, B meson, Bottom mesons, Branching (polymer chemistry), 7. Clean energy, 01 natural sciences, Lower limit, HEP, NO, Nuclear and elementary particle physics: 431 [VDP], 0103 physical sciences, 010306 general physics, Bar (unit)
Abstract

A study of the two-body decays B±→XccK±, where Xcc refers to one charmonium state, is reported by the BABAR Collaboration using a data sample of 424 fb-1. The absolute determination of branching fractions for these decays are significantly improved compared to previous BABAR measurements. Evidence is found for the decay B+→X(3872)K+ at the 3σ level. The absolute branching fraction B[B+→X(3872)K+]=[2.1±0.6(stat)±0.3(syst)]×10-4 is measured for the first time. It follows that B[X(3872)→J/ψπ+π-]=(4.1±1.3)%, supporting the hypothesis of a molecular component for this resonance., This work is supported by the U.S. Department of Energy and National Science Foundation, the Natural Sciences and Engineering Research Council (Canada), Institute of High Energy Physics (China), the Commissariat `a l’Energie Atomique and Institut National de Physique Nucl´eaire et de Physique des Particules (France), the Bundesministerium für Bildung und Forschung and Deutsche Forschungsgemeinschaft (Germany), the Istituto Nazionale di Fisica Nucleare (Italy), the Foundation for Fundamental Research on Matter (The Netherlands), the Research Council of Norway, the Ministry of Science and Technology of the Russian Federation, and the Particle Physics and Astronomy Research Council (United Kingdom). Individuals have received support from CONACyT (Mexico), the A. P. Sloan Foundation, the Research Corporation, and the Alexander von Humboldt Foundation.

Published
2020

21. Direct Observation of C2O4•– and CO2•– by Oxidation of Oxalate within Nanogap of Scanning Electrochemical Microscope

Author

Tianhan Kai, Sarah Jean Johnson, Allen J. Bard, Hyun S. Ahn, and Min Zhou

Subjects
endocrine system, Microscope, Chemistry, Direct observation, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Photochemistry, Electrochemistry, 01 natural sciences, Biochemistry, Catalysis, Oxalate, 0104 chemical sciences, law.invention, chemistry.chemical_compound, Colloid and Surface Chemistry, law, 0210 nano-technology, Chemiluminescence
Abstract

Oxalate oxidation in the presence of different oxidized luminophores leads to the emission of light and has been studied extensively in electrogenerated chemiluminescence (ECL). The proposed mechan...

Published
2018
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22. Direct photoelectrochemical characterization of photocatalytic H, N doped TiO2 powder suspensions

Author

Ki Min Nam, Hyun S. Park, Heung Chan Lee, Allen J. Bard, and Sung Ki Cho

Subjects
Hydrogen, General Chemical Engineering, Inorganic chemistry, Doping, chemistry.chemical_element, Electron donor, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Electrochemistry, 01 natural sciences, 0104 chemical sciences, Analytical Chemistry, Amorphous solid, chemistry.chemical_compound, chemistry, Chemical engineering, Rutile, Photocatalysis, 0210 nano-technology, Visible spectrum
Abstract

The photoelectrochemical (PEC) properties of photocatalysts as powder suspensions were measured directly by an electrochemical technique that allows the action spectrum and relative activities to be measured. This technique was applied to various photocatalyst powders, such as TiO2 synthesized in various ways to produce materials claimed to be active in the visible region (e.g. so-called “black TiO2”), in the presence of a sacrificial electron donor reactants. Hydrogen treated TiO2 photocatalytic powders do not show visible light photocurrents, and ammonia treated TiO2 photocatalyst powders can utilized visible lights photoelectrochemically although their incident photon to current efficiency, at 450, is two hundredths of that at 320 nm. Structural and elemental analysis of these types of modified TiO2 revealed that an amorphous layer and slight nitrogen doping on the crystalline surface provides the capability of visible light utilization for rutile TiO2. The generality of the technique with other particles (BiVO4, WO3) and its advantages over simple photodecomposition experiments is also discussed.

Published
2018
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23. Electrochemically controllable coating of a functional silicon film on carbon materials

Author

Haijia Zhao, Allen J. Bard, Hongwei Xie, Huayi Yin, and Jin-Yun Liao

Subjects
Materials science, Silicon, Electrolytic cell, business.industry, General Chemical Engineering, Nanowire, chemistry.chemical_element, 02 engineering and technology, Substrate (electronics), engineering.material, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Anode, chemistry, Coating, Chemical engineering, Photovoltaics, Electrochemistry, engineering, Graphite, 0210 nano-technology, business
Abstract

A silicon deposit of various forms was successfully coated on graphite by electrodeposition in molten CaCl2 containing nano-SiO2 as a silicon precursor. The morphologies of the deposited silicon can be tuned from Si nanowires to a dense film by controlling constant electrolysis cell voltage. In addition to controlling electrochemical polarizations, the substrate plays a key role in forming a dense silicon film. By analyzing the interface between the Si film and graphite substrate, a thin transition layer comprising of Si, SiC and C enables the good adhesion of the Si film with the carbon substrate and thereby helps the growth of a dense Si film. Besides the application for photovoltaics, the electrolytic p-type Si film was employed as a binder-free anode for lithium-ion batteries delivering a capacity of over 2500 mAh g−1 in the first 10 cycles and retaining 800 mAh g−1 after 40 cycles. Moreover, this method was applied for coating Si on carbon fibers, which could be a general way to prepare Si with controllable forms and silicon/carbon core-shell structures for functional materials.

Published
2018
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24. High-Performance Photodetectors Based on Solution-Processed Epitaxial Grown Hybrid Halide Perovskites

Author

Allen J. Bard, Edward T. Yu, Jack C. Lee, Hsien-Yi Hsu, and Li Ji

Subjects
Materials science, Silicon, Halide, Photodetector, chemistry.chemical_element, Bioengineering, 02 engineering and technology, 010402 general chemistry, Epitaxy, 01 natural sciences, Crystallinity, symbols.namesake, General Materials Science, business.industry, Mechanical Engineering, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, Semiconductor, chemistry, symbols, Optoelectronics, 0210 nano-technology, business, Raman spectroscopy, Single crystal
Abstract

Hybrid organic–inorganic halide perovskites (HOIPs) have recently attracted tremendous attention because of their excellent semiconducting and optoelectronic properties, which exist despite their morphology and crystallinity being far inferior to those of more mature semiconductors, such as silicon and III–V compound semiconductors. Heteroepitaxy can provide a route to achieving high-performance HOIP devices when high crystalline quality and smooth morphology are required, but work on heteroepitaxial HOIPs has not previously been reported. Here, we demonstrate epitaxial growth of methylammonium lead iodide (MAPbI3) on single crystal KCl substrates with smooth morphology and the highest carrier recombination lifetime (∼213 ns) yet reported for nonsingle crystalline MAPbI3. Experimental Raman spectra agree well with theoretical calculations, presenting in particular a sharp peak at 290 cm–1 for the torsional mode of the organic cations, a marker of orientational order and typically lacking in previous repor...

Published
2018
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25. Scanning electrochemical microscopy at the nanometer level

Author

Cynthia G. Zoski, Allen J. Bard, and Tianhan Kai

Subjects
Fabrication, Materials science, Metals and Alloys, Nanoparticle, Nanotechnology, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Catalysis, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Scanning electrochemical microscopy, Nano, Electrode, Materials Chemistry, Ceramics and Composites, Nanometre, Instrumentation (computer programming), 0210 nano-technology, Nanoscopic scale
Abstract

This review describes how one can perform nanometer (nm)-scale SECM experiments through advances in tip fabrication and positioning and instrumentation design. Basic SECM methodology including instrumentation and feedback and generation/collection modes are discussed. Aspects of nanoscale SECM including fabrication of nm-sized electrodes and nano SECM instrumentation are also described. State of the art applications related to nanogaps (i.e., rapid homogeneous reactions and short-lived intermediates; heterogeneous electron transfer kinetics; nanoparticles (NPs) and clusters) and nanoscale imaging (e.g., single NPs, single biological samples, combined methods) are described. Future possibilities and prospects are suggested that might lead to even better resolution, thus introducing SECM electrochemical imaging to the single atom level.

Published
2018
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26. Scanning Electrochemical Microscopy

Author

Allen J. Bard, Michael V. Mirkin, Allen J. Bard, and Michael V. Mirkin

Subjects
Electrochemistry, Scanning electron microscopy--Methodology, Scanning electrochemical microscopy
Abstract

Because of its simplicity of use and quantitative results, Scanning Electrochemical Microscopy (SECM) has become an indispensable tool for the study of surface reactivity. The fast expansion of the SECM field over several years has been fueled by the introduction of new probes, commercially available instrumentation, and new practical applications. Scanning Electrochemical Microscopy, Third Edition offers essential background and in-depth overviews of specific applications in self-contained chapters.The vitality and growing popularity of SECM over the past 30+ years have largely been determined by its versatility and capability to remain useful in the changing scientific and technological environments. New applications reported during the last decade reflect significant current activity in biomedical and energy-related research. This thoroughly updated edition provides up-to-date comprehensive reviews of different aspects of SECM.New chapters by renowned professionals in the field cover recent advances in different areas of SECM including nanoSECM, surface reactions and films, batteries, and fuel cells. Expanded coverage of electrocatalysis and surface interrogation as well as photoelectrochemistry and photoelectrocatalysis are also provided.Useful for a broad range of interdisciplinary research—from biological systems to nanopatterning—this book is invaluable to all interested in learning and applying SECM.

Published
2022

27. Ultrasensitive Electroanalysis: Femtomolar Determination of Lead, Cobalt, and Nickel

Author

Allen J. Bard, Michael V. Mirkin, Jeffrey E. Dick, Keke Hu, and Min Zhou

Subjects
Electrolysis of water, 010405 organic chemistry, Inorganic chemistry, Oxide, chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, Amperometry, 0104 chemical sciences, Analytical Chemistry, Metal, chemistry.chemical_compound, Nickel, chemistry, visual_art, Electrode, visual_art.visual_art_medium, Carbon, Cobalt
Abstract

We demonstrate the feasibility of attaining femtomolar limits of quantitation in electroanalysis. The method employed is based on electrocatalytic amplification, where small quantities of metal deposit performed on a carbon electrode causes a large increase in the observed current, for example, for the oxidation of water. We show calibration curves at the femtomolar level for cobalt, nickel, and lead ions on carbon ultramicroelectrodes (CUMEs), ca. 500 nm radii. The CUME was biased at a potential where the ion would deposit as the metal oxide, MOx, and a high concentration of species that is oxidized at the deposit is present in solution. Blips were observed in the amperometric i-t response, and their frequency scaled linearly with the concentration of ions at the femtomolar level. From these results, the limits of quantitation for cobalt, nickel, and lead ions were reported at 10 s of femtomolar level for the first time.

Published
2017
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28. Electrodeposition of Isolated Platinum Atoms and Clusters on Bismuth—Characterization and Electrocatalysis

Author

Allen J. Bard, Jeffrey E. Dick, and Min Zhou

Subjects
Analytical chemistry, chemistry.chemical_element, Nanotechnology, Ultramicroelectrode, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Electrochemistry, Electrocatalyst, 01 natural sciences, Biochemistry, Catalysis, 0104 chemical sciences, Bismuth, Colloid and Surface Chemistry, chemistry, Plating, Cluster (physics), 0210 nano-technology, Platinum, Voltammetry
Abstract

We describe a method for the electrodeposition of an isolated single Pt atom or small cluster, up to 9 atoms, on a bismuth ultramicroelectrode (UME). This deposition was immediately followed by electrochemical characterization via the hydrogen evolution reaction (HER) that occurs readily on the electrodeposited Pt but not on Bi. The observed voltammetric current plateau, even for a single atom, which behaves as an electrode, allows the estimation of deposit size. Pt was plated from solutions of femtomolar PtCl62–, which allowed precise control of the arrival of ions and thus the plating rate on the Bi UME, to one ion every few seconds. This allowed the atom-by-atom fabrication of isolated platinum deposits, ranging from single atoms to 9-atom clusters. The limiting currents in voltammetry gave the size and number of atoms of the clusters. Given the stochasticity of the plating process, we show that the number of atoms plated over a given time (10 and 20 s) follows a Poisson distribution. Taking the potent...

Published
2017
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29. Electrochemical Formation of a p–n Junction on Thin Film Silicon Deposited in Molten Salt

Author

Edward T. Yu, Allen J. Bard, Li Ji, Xingli Zou, Taeho Lim, and Xiao Yang

Subjects
inorganic chemicals, Silicon, Inorganic chemistry, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, complex mixtures, 01 natural sciences, Biochemistry, Catalysis, Monocrystalline silicon, Colloid and Surface Chemistry, Thin film, Molten salt, Silicon oxide, Diode, Chemistry, business.industry, technology, industry, and agriculture, Nanocrystalline silicon, General Chemistry, equipment and supplies, 021001 nanoscience & nanotechnology, 0104 chemical sciences, stomatognathic diseases, Optoelectronics, 0210 nano-technology, business, p–n junction
Abstract

Herein we report the demonstration of electrochemical deposition of silicon p-n junctions all in molten salt. The results show that a dense robust silicon thin film with embedded junction formation can be produced directly from inexpensive silicates/silicon oxide precursors by a two-step electrodeposition process. The fabricated silicon p-n junction exhibits clear diode rectification behavior and photovoltaic effects, indicating promise for application in low-cost silicon thin film solar cells.

Published
2017
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30. Toward Cost‐Effective Manufacturing of Silicon Solar Cells: Electrodeposition of High‐Quality Si Films in a CaCl 2 ‐based Molten Salt

Author

Xingli Zou, Taeho Lim, Ji Zhao, Xiao Yang, Allen J. Bard, Li Ji, and Edward T. Yu

Subjects
Materials science, Silicon, 020209 energy, Inorganic chemistry, 0211 other engineering and technologies, chemistry.chemical_element, 02 engineering and technology, Electrolyte, Catalysis, chemistry.chemical_compound, Impurity, 0202 electrical engineering, electronic engineering, information engineering, 021108 energy, Molten salt, Photocurrent, business.industry, Photovoltaic system, General Medicine, General Chemistry, 021001 nanoscience & nanotechnology, Semiconductor, Chemical engineering, chemistry, 0210 nano-technology, business, Fluoride
Abstract

Electrodeposition of Si films from a Si-containing electrolyte is a cost-effective approach for the manufacturing of solar cells. Proposals relying on fluoride-based molten salts have suffered from low product quality due to difficulties in impurity control. Here we demonstrate the successful electrodeposition of high-quality Si films from a CaCl2-based molten salt. Soluble SiIV−O anions generated from solid SiO2 are electrodeposited onto a graphite substrate to form a dense film of crystalline Si. Impurities in the deposited Si film are controlled at low concentrations (both B and P are less than 1 ppm). In the photoelectrochemical measurements, the film shows p-type semiconductor character and large photocurrent. A p–n junction fabricated from the deposited Si film exhibits clear photovoltaic effects. This study represents the first step to the ultimate goal of developing a cost-effective manufacturing process for Si solar cells based on electrodeposition.

Published
2017
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31. Visible Light Photoelectrochemical Properties of PbCrO4, Pb2CrO5, and Pb5CrO8

Author

Heung Chan Lee, Allen J. Bard, Sung Ki Cho, Hyun S. Park, and Ki Min Nam

Subjects
Photocurrent, Materials science, Absorption spectroscopy, Energy conversion efficiency, Analytical chemistry, Oxide, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Scanning electrochemical microscopy, chemistry.chemical_compound, General Energy, chemistry, Electrode, Physical and Theoretical Chemistry, 0210 nano-technology, Absorption (electromagnetic radiation), Visible spectrum
Abstract

Photoactivities of lead chromates with various combinations of Pb and Cr are rapidly screened using scanning electrochemical microscopy (SECM). In the rapid screening investigation, the metal oxide spot electrode with a Pb/Cr ratio of 2:1 exhibits the highest photoactivity among the semiconductor prepared with different compositions. The photoactivity and electrochemical properties of thin-film electrodes of PbCrO4, Pb2CrO5, and Pb5CrO8 are further studied following the combinatorial screening. In the bulk electrode measurements, the Pb2CrO5 bulk electrode displays the highest photocurrent of 0.23 mA/cm2 for SO32– oxidation at 0.4 V vs Ag/AgCl under 100 mW/cm2 UV–vis light irradiation. Pb2CrO5 presents visible light activity with an absorption wavelength up to 550 nm and an incident photon to current conversion efficiency (IPCE) of 10% at the wavelength of 340 nm. The onset wavelength observed in the UV–vis absorption spectrum increases with increasing Pb contents in lead chromates. Optically obtained dir...

Published
2017
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32. Detection of an Unstable Intermediate in Br − Electro-oxidation to Br 3 − on a Platinum Electrode in Nitrobenzene by Scanning Electrochemical Microscopy

Author

Jinho Chang, Allen J. Bard, and Brent Bennett

Subjects
Reaction mechanism, Bromine, General Chemical Engineering, Analytical chemistry, chemistry.chemical_element, Substrate (chemistry), 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Electrochemistry, 01 natural sciences, 0104 chemical sciences, Nitrobenzene, chemistry.chemical_compound, Scanning electrochemical microscopy, chemistry, Cyclic voltammetry, 0210 nano-technology, Platinum
Abstract

We report the detection of an unstable intermediate generated during Br − oxidation to Br 3 − in nitrobenzene by scanning electrochemical microscopy (SECM), and we attempt to simulate the collection of the intermediate using a proposed mechanism of Br − oxidation to Br 3 − . At a distance of ∼ 3.5 μm between the tip and the substrate electrode in the SECM experiment, we observed two waves as we measured the collection efficiency, N ss , while holding the tip at an anodic potential and scanning the substrate toward cathodic potentials. The second wave obtained at more negative substrate potentials was associated with the collection of Br 3 − , and the first wave was associated with the collection of an intermediate generated in Br − oxidation to Br 3 − . The N ss as a function of d , estimated at the constant substrate potential of 0.27 V vs. TMPD/TMPD + ·, abruptly increased as d was brought below 2.5 μm. We simulated this approach curve by using the following mechanism of Br − oxidation to Br 3 − : (1) Br − + e ⇋ Br·, (2) 2Br· ⇋ Br 2 , (3) Br· + Br − ⇋ Br 2 − ·, (4) Br 2 − · + e ⇋ Br 2 , and (5) Br 2 + Br − ⇋ Br 3 − .

Published
2017
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33. Cathodically Dissolved Platinum Resulting from the O2 and H2O2 Reduction Reactions on Platinum Ultramicroelectrodes

Author

Stephen J. Percival, Allen J. Bard, and Jeffrey E. Dick

Subjects
endocrine system diseases, Chemistry, Radical, Inorganic chemistry, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Platinum nanoparticles, 01 natural sciences, Redox, female genital diseases and pregnancy complications, 0104 chemical sciences, Analytical Chemistry, chemistry.chemical_compound, Platinum black, Oxidizing agent, Cyclic voltammetry, 0210 nano-technology, Platinum, Hydrogen peroxide
Abstract

The cathodic dissolution of platinum, resulting from the oxygen reduction reaction (ORR) or hydrogen peroxide reduction on platinum, has been investigated. Highly oxidizing hydroxyl radicals (OH•) are believed to be the species responsible for the platinum dissolution phenomenon. These radicals are produced from the ORR byproduct, hydrogen peroxide, through a 1 electron reduction pathway (H2O2 + e– → OH• + OH–). Platinum ultramicroelectrodes (UMEs) were polarized sufficiently negative to drive the ORR or H2O2 reduction on the platinum surface, mainly using square wave potential pulses but constant applied potential and cyclic voltammetry (CV) were also investigated. The dissolved platinum was detected using a femtomolar level detection technique which involves reducing platinum ions to platinum metal species followed by an electrocatalytic amplification of proton reduction on an inert carbon fiber electrode. This method has allowed the quantification of the amount of platinum metal dissolved into the solu...

Published
2017
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34. Measurements of the Absolute Branching Fractions of $B^\pm \to K^\pm X_{c\bar c}$

Author

Aubert, B., Barate, R., Boutigny, D., Couderc, F., Karyotakis, Y., Lees, J.P., Poireau, V., Tisserand, V., Zghiche, A., Grauges, E., Palano, A., Pappagallo, M., Pompili, A., C. Chen, J., D. Qi, N., Rong, G., Wang, P., S. Zhu, Y., Eigen, G., Ofte, I., Stugu, B., S. Abrams, G., Battaglia, M., B. Breon, A., N. Brown, D., Button-Shafer, J., N. Cahn, R., Charles, E., T. Day, C., S. Gill, M., V. Gritsan, A., Groysman, Y., G. Jacobsen, R., W. Kadel, R., Kadyk, J., T. Kerth, L., G. Kolomensky, Yu., Kukartsev, G., Lynch, G., M. Mir, L., J. Oddone, P., J. Orimoto, T., Pripstein, M., Roe, N.A., T. Ronan, M., Wenzel, W.A., Barrett, M., E. Ford, K., J. Harrison, T., J. Hart, A., M. Hawkes, C., E. Morgan, S., T. Watson, A., Fritsch, M., Goetzen, K., Held, T., Koch, H., Lewandowski, B., Pelizaeus, M., Peters, K., Schroeder, T., Steinke, M., T. Boyd, J., P. Burke, J., Chevalier, N., N. Cottingham, W., Cuhadar-Donszelmann, T., G. Fulsom, B., Hearty, C., S. Knecht, N., S. Mattison, T., A. Mckenna, J., Khan, A., Kyberd, P., Saleem, M., Teodorescu, L., E. Blinov, A., E. Blinov, V., D. Bukin, A., P. Druzhinin, V., B. Golubev, V., A. Kravchenko, E., P. Onuchin, A., I. Serednyakov, S., I. Skovpen, Yu., P. Solodov, E., N. Yushkov, A., Best, D., Bondioli, M., Bruinsma, M., Chao, M., Curry, S., Eschrich, I., Kirkby, D., J. Lankford, A., Lund, P., Mandelkern, M., K. Mommsen, R., Roethel, W., P. Stoker, D., Buchanan, C., L. Hartfiel, B., J. R. Weinstein, A., D. Foulkes, S., W. Gary, J., Long, O., C. Shen, B., Wang, K., Zhang, L., del Re, D., K. Hadavand, H., J. Hill, E., B. Macfarlane, D., P. Paar, H., Rahatlou, S., Sharma, V., W. Berryhill, J., Campagnari, C., Cunha, A., Dahmes, B., M. Hong, T., A. Mazur, M., D. Richman, J., Verkerke, W., W. Beck, T., M. Eisner, A., J. Flacco, C., Heusch, C.A., Kroseberg, J., S. Lockman, W., Nesom, G., Schalk, T., A. Schumm, B., Seiden, A., Spradlin, P., C. Williams, D., G. Wilson, M., Albert, J., Chen, E., P. Dubois-Felsmann, G., Dvoretskii, A., G. Hitlin, D., S. Minamora, J., Narsky, I., Piatenko, T., C. Porter, F., Ryd, A., Samuel, A., Andreassen, R., Mancinelli, G., T. Meadows, B., D. Sokoloff, M., Blanc, F., Bloom, P., Chen, Si, T. Ford, W., F. Hirschauer, J., Kreisel, A., Nauenberg, U., Olivas, A., O. Ruddick, W., G. Smith, J., A. Ulmer, K., R. Wagner, S., Zhang, J., Chen, A., A. Eckhart, E., Soffer, A., H. Toki, W., J. Wilson, R., Zeng, Q., Altenburg, D., Feltresi, E., Hauke, A., Spaan, B., Brandt, T., Brose, J., Dickopp, M., Klose, V., M. Lacker, H., Nogowski, R., Otto, S., Petzold, A., Schubert, J., R. Schubert, K., Schwierz, R., E. Sundermann, J., Bernard, D., Bonneaud, G.R., Grenier, P., Schrenk, S., Thiebaux, C., Vasileiadis, G., Verderi, M., J. Bard, D., J. Clark, P., Gradl, W., Muheim, F., Playfer, S., Xie, Y., Andreotti, M., Azzolini, V., Bettoni, D., Bozzi, C., Calabrese, R., Cibinetto, G., Luppi, E., Negrini, M., Piemontese, L., Anulli, F., Baldini-Ferroli, R., Calcaterra, A., de Sangro, R., Finocchiaro, G., Patteri, P., M. Peruzzi, I., Piccolo, M., Zallo, A., Buzzo, A., Capra, R., Contri, R., Lo Vetere, M., Macri, M., R. Monge, M., Passaggio, S., Patrignani, C., Robutti, E., Santroni, A., Tosi, S., Brandenburg, G., S. Chaisanguanthum, K., Morii, M., Won, E., Wu, J., S. Dubitzky, R., Langenegger, U., Marks, J., Schenk, S., Uwer, U., Schott, G., Bhimji, W., Bowerman, D.A., D. Dauncey, P., Egede, U., L. Flack, R., R. Gaillard, J., A. Nash, J., B. Nikolich, M., Panduro Vazquez, W., Chai, X., J. Charles, M., F. Mader, W., Mallik, U., K. Mohapatra, A., Ziegler, V., Cochran, J., B. Crawley, H., Eyges, V., T. Meyer, W., Prell, S., I. Rosenberg, E., E. Rubin, A., Yi, J., Arnaud, N., Davier, M., Giroux, X., Grosdidier, G., Hocker, A., Le Diberder, F., Lepeltier, V., Lutz, A.M., Oyanguren, A., Petersen, T.C., Plaszczynski, Stéphane, Rodier, S., Roudeau, P., Schune, M.H., Stocchi, A., Wormser, G., H. Cheng, C., J. Lange, D., C. Simani, M., M. Wright, D., J. Bevan, A., Chavez, C.A., J. Forster, I., R. Fry, J., Gabathuler, E., Gamet, R., A. George, K., E. Hutchcroft, D., J. Parry, R., J. Payne, D., C. Schofield, K., Touramanis, C., M. Cormack, C., Di Lodovico, F., Menges, W., Sacco, R., L. Brown, C., Cowan, G., U. Flaecher, H., G. Green, M., Hopkins, D.A., S. Jackson, P., R. Mcmahon, T., Ricciardi, S., Salvatore, F., Brown, D., L. Davis, C., Allison, J., R. Barlow, N., J. Barlow, R., L. Edgar, C., C. Hodgkinson, M., P. Kelly, M., D. Lafferty, G., T. Naisbit, M., C. Williams, J., Chen, C., D. Hulsbergen, W., Jawahery, A., Kovalskyi, D., K. Lae, C., Roberts, D.A., Simi, G., Blaylock, G., Dallapiccola, C., Hertzbach, S.S., Kofler, R., B. Koptchev, V., Li, Xiaojian, B. Moore, T., Saremi, S., Staengle, H., Willocq, S., Cowan, R., Koeneke, K., Sciolla, G., J. Sekula, S., Spitznagel, M., Taylor, F., K. Yamamoto, R., Kim, H., M. Patel, P., H. Robertson, S., Lazzaro, A., Lombardo, V., Palombo, F., M. Bauer, J., Cremaldi, L., Eschenburg, V., Godang, R., Kroeger, R., Reidy, J., Sanders, D.A., J. Summers, D., W. Zhao, H., Brunet, S., Cote, D., Taras, P., Viaud, B., Nicholson, H., Cavallo, N., de Nardo, G., Fabozzi, F., Gatto, C., Lista, L., Monorchio, D., Paolucci, P., Piccolo, D., Sciacca, C., Baak, M., Bulten, H., Raven, G., L. Snoek, H., Wilden, L., P. Jessop, C., M. Losecco, J., Allmendinger, T., Benelli, G., K. Gan, K., Honscheid, K., Hufnagel, D., D. Jackson, P., Kagan, H., Kass, R., Pulliam, T., M. Rahimi, A., Ter-Antonyan, R., K. Wong, Q., Brau, J., Frey, R., Igonkina, O., Lu, M., T. Potter, C., B. Sinev, N., Strom, D., Strube, J., Torrence, E., Galeazzi, F., Margoni, M., Morandin, M., Posocco, M., Rotondo, M., Simonetto, F., Stroili, R., Voci, C., Benayoun, M., Briand, H., Chauveau, J., David, P., del Buono, L., de La Vaissiere, C., Hamon, O., John, M.J.J., Leruste, P., Malcles, J., Ocariz, J., Roos, L., Therin, G., K. Behera, P., Gladney, L., H. Guo, Q., Panetta, J., Biasini, M., Covarelli, R., Pacetti, S., Pioppi, M., Angelini, C., Batignani, G., Bettarini, S., Bucci, F., Calderini, G., Carpinelli, M., Cenci, R., Forti, F., A. Giorgi, M., Lusiani, A., Marchiori, G., Morganti, M., Neri, N., Paoloni, E., Rama, M., Rizzo, G., Walsh, J., Haire, M., Judd, D., E. Wagoner, D., Biesiada, J., Danielson, N., Elmer, P., P. Lau, Y., Lu, C., Olsen, J., J. S. Smith, A., V. Telnov, A., Bellini, F., Cavoto, G., d'Orazio, A., Di Marco, E., Faccini, R., Ferrarotto, F., Ferroni, F., Gaspero, M., Li Gioi, L., A. Mazzoni, M., Morganti, S., Piredda, G., Polci, F., Safai Tehrani, F., Voena, C., Schr¨oder, H., Wagner, G., Waldi, R., Adye, T., De, N., Franek, B., P. Gopal, G., O. Olaiya, E., F. Wilson, F., Aleksan, R., Emery, S., Gaidot, A., F. Ganzhur, S., Graziani, G., Hamel de Monchenault, G., Kozanecki, W., Legendre, M., W. London, G., Mayer, B., Vasseur, G., Yèche, Ch., Zito, M., V. Purohit, M., W. Weidemann, A., R. Wilson, J., X. Yumiceva, F., Abe, T., T. Allen, M., Aston, D., Bartoldus, R., Berger, N., M. Boyarski, A., L. Buchmueller, O., Claus, R., P. Coleman, J., R. Convery, M., Cristinziani, M., C. Dingfelder, J., Dong, D., Dorfan, J., Dujmic, D., Dunwoodie, W., Fan, S., C. Field, R., Glanzman, T., J. Gowdy, S., Hadig, T., Halyo, V., Hast, C., Hryn'Ova, T., R. Innes, W., H. Kelsey, M., Kim, P., L. Kocian, M., W. G. S. Leith, D., Libby, J., Luitz, S., Luth, V., L. Lynch, H., Marsiske, H., Messner, R., R. Muller, D., P. O'Grady, C., E. Ozcan, V., Perazzo, A., Perl, M., N. Ratcliff, B., Roodman, A., A. Salnikov, A., H. Schindler, R., Schwiening, J., Snyder, A., Stelzer, J., Su, D., K. Sullivan, M., Suzuki, K., K. Swain, S., M. Thompson, J., Va'Vra, J., van Bakel, N., Weaver, M., J. Wisniewski, W., Wittgen, M., H. Wright, D., K. Yarritu, A., Yi, K., C. Young, C., R. Burchat, P., J. Edwards, A., Majewski, S.A., A. Petersen, B., Roat, C., Ahmed, M., Ahmed, Mohamed-Salem, S. Alam, M., Bula, R., A. Ernst, J., A. Saeed, M., R. Wappler, F., B. Zain, S., Bugg, W., Krishnamurthy, M., M. Spanier, S., Eckmann, R., L. Ritchie, J., Satpathy, A., F. Schwitters, R., M. Izen, J., Kitayama, I., C. Lou, X., Ye, S., Bianchi, F., Bona, M., Gallo, F., Gamba, D., Bomben, M., Bosisio, L., Cartaro, C., Cossutti, F., Della Ricca, G., Dittongo, S., Grancagnolo, S., Lanceri, L., Vitale, L., Martinez-Vidal, F., S. Panvini, R., Sw. Banerjee, ‡, Bhuyan, B., M. Brown, C., Fortin, D., Hamano, K., Kowalewski, R., M. Roney, J., J. Sobie, R., Back, J.J., F. Harrison, P., E. Latham, T., B. Mohanty, G., R. Band, H., Chen, X., Cheng, B., Dasu, S., Datta, M., M. Eichenbaum, A., T. Flood, K., Graham, M., Hollar, J.J., R. Johnson, J., E. Kutter, P., Li, H., Liu, R., Mellado, B., Mihalyi, A., Pan, Y., Pierini, M., Prepost, R., Tan, P., L. Wu, S., Yu, Z., Neal, H., Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de l'Accélérateur Linéaire (LAL), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, BaBar, Laboratoire d'Annecy de Physique des Particules (LAPP), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), BABAR, Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
+J%2Fpsi%283100%29+pi%2B+pi%22">X(3872) --> J/psi(3100) pi+ pi, S041.171, X(3872): branching ratio, B+: branching ratio: measured, +charmonium+K%2B%22">B+ --> charmonium K+, FOS: Physical sciences, electron positron: annihilation, S041.439, charmonium: electroproduction, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), +X%283872%29+K%22">B- --> X(3872) K, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], S041.20, +charmonium+K%22">B- --> charmonium K, S041.360, 13.25.Hw, 14.40.Gx, S041.266, High Energy Physics::Phenomenology, B-: branching ratio: measured, S041.265, S041.440, electron positron: colliding beams, B-: hadronic decay, SLAC PEP Stor, BaBar, B+: hadronic decay, Elementary Particles and Fields, +X%283872%29+K%2B%22">B+ --> X(3872) K+, High Energy Physics::Experiment, experimental results
Abstract

A study of the two body decays $B^\pm\rightarrow X_{c\bar c}K^\pm$, where X$_{c\bar c}$ refers to one charmonium state, is reported by BaBar collaboration using a data sample of 424 fb$^{-1}$. The absolute determination of branching fractions for these decays are significantly improved compared to previous BaBaR measurements. Evidence is found for the decay $B^+\rightarrow X(3872)K^+$ at the $3\sigma$ level. The absolute branching fraction ${\cal B}(B^+\rightarrow X(3872)K^+) = (2.1\pm0.6({\rm stat})\pm0.3({\rm syst}))\times 10^{-4}$ is measured for the first time. It follows that ${\cal B}(X(3872)\rightarrow J/\psi\pi^+\pi^-)=(4.1\pm1.3)\%$, supporting the hypothesis of a molecular component for this resonance., Comment: 8 pages 6 figures

Published
2019
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38. LSST: from Science Drivers to Reference Design and Anticipated Data Products

Author

Željko Ivezić, Steven M. Kahn, J. Anthony Tyson, Bob Abel, Emily Acosta, Robyn Allsman, David Alonso, Yusra AlSayyad, Scott F. Anderson, John Andrew, James Roger P. Angel, George Z. Angeli, Reza Ansari, Pierre Antilogus, Constanza Araujo, Robert Armstrong, Kirk T. Arndt, Pierre Astier, Éric Aubourg, Nicole Auza, Tim S. Axelrod, Deborah J. Bard, Jeff D. Barr, Aurelian Barrau, James G. Bartlett, Amanda E. Bauer, Brian J. Bauman, Sylvain Baumont, Ellen Bechtol, Keith Bechtol, Andrew C. Becker, Jacek Becla, Cristina Beldica, Steve Bellavia, Federica B. Bianco, Rahul Biswas, Guillaume Blanc, Jonathan Blazek, Roger D. Blandford, Josh S. Bloom, Joanne Bogart, Tim W. Bond, Michael T. Booth, Anders W. Borgland, Kirk Borne, James F. Bosch, Dominique Boutigny, Craig A. Brackett, Andrew Bradshaw, William Nielsen Brandt, Michael E. Brown, James S. Bullock, Patricia Burchat, David L. Burke, Gianpietro Cagnoli, Daniel Calabrese, Shawn Callahan, Alice L. Callen, Jeffrey L. Carlin, Erin L. Carlson, Srinivasan Chandrasekharan, Glenaver Charles-Emerson, Steve Chesley, Elliott C. Cheu, Hsin-Fang Chiang, James Chiang, Carol Chirino, Derek Chow, David R. Ciardi, Charles F. Claver, Johann Cohen-Tanugi, Joseph J. Cockrum, Rebecca Coles, Andrew J. Connolly, Kem H. Cook, Asantha Cooray, Kevin R. Covey, Chris Cribbs, Wei Cui, Roc Cutri, Philip N. Daly, Scott F. Daniel, Felipe Daruich, Guillaume Daubard, Greg Daues, William Dawson, Francisco Delgado, Alfred Dellapenna, Robert de Peyster, Miguel de Val-Borro, Seth W. Digel, Peter Doherty, Richard Dubois, Gregory P. Dubois-Felsmann, Josef Durech, Frossie Economou, Tim Eifler, Michael Eracleous, Benjamin L. Emmons, Angelo Fausti Neto, Henry Ferguson, Enrique Figueroa, Merlin Fisher-Levine, Warren Focke, Michael D. Foss, James Frank, Michael D. Freemon, Emmanuel Gangler, Eric Gawiser, John C. Geary, Perry Gee, Marla Geha, Charles J. B. Gessner, Robert R. Gibson, D. Kirk Gilmore, Thomas Glanzman, William Glick, Tatiana Goldina, Daniel A. Goldstein, Iain Goodenow, Melissa L. Graham, William J. Gressler, Philippe Gris, Leanne P. Guy, Augustin Guyonnet, Gunther Haller, Ron Harris, Patrick A. Hascall, Justine Haupt, Fabio Hernandez, Sven Herrmann, Edward Hileman, Joshua Hoblitt, John A. Hodgson, Craig Hogan, James D. Howard, Dajun Huang, Michael E. Huffer, Patrick Ingraham, Walter R. Innes, Suzanne H. Jacoby, Bhuvnesh Jain, Fabrice Jammes, James Jee, Tim Jenness, Garrett Jernigan, Darko Jevremović, Kenneth Johns, Anthony S. Johnson, Margaret W. G. Johnson, R. Lynne Jones, Claire Juramy-Gilles, Mario Jurić, Jason S. Kalirai, Nitya J. Kallivayalil, Bryce Kalmbach, Jeffrey P. Kantor, Pierre Karst, Mansi M. Kasliwal, Heather Kelly, Richard Kessler, Veronica Kinnison, David Kirkby, Lloyd Knox, Ivan V. Kotov, Victor L. Krabbendam, K. Simon Krughoff, Petr Kubánek, John Kuczewski, Shri Kulkarni, John Ku, Nadine R. Kurita, Craig S. Lage, Ron Lambert, Travis Lange, J. Brian Langton, Laurent Le Guillou, Deborah Levine, Ming Liang, Kian-Tat Lim, Chris J. Lintott, Kevin E. Long, Margaux Lopez, Paul J. Lotz, Robert H. Lupton, Nate B. Lust, Lauren A. MacArthur, Ashish Mahabal, Rachel Mandelbaum, Thomas W. Markiewicz, Darren S. Marsh, Philip J. Marshall, Stuart Marshall, Morgan May, Robert McKercher, Michelle McQueen, Joshua Meyers, Myriam Migliore, Michelle Miller, David J. Mills, Connor Miraval, Joachim Moeyens, Fred E. Moolekamp, David G. Monet, Marc Moniez, Serge Monkewitz, Christopher Montgomery, Christopher B. Morrison, Fritz Mueller, Gary P. Muller, Freddy Muñoz Arancibia, Douglas R. Neill, Scott P. Newbry, Jean-Yves Nief, Andrei Nomerotski, Martin Nordby, Paul O’Connor, John Oliver, Scot S. Olivier, Knut Olsen, William O’Mullane, Sandra Ortiz, Shawn Osier, Russell E. Owen, Reynald Pain, Paul E. Palecek, John K. Parejko, James B. Parsons, Nathan M. Pease, J. Matt Peterson, John R. Peterson, Donald L. Petravick, M. E. Libby Petrick, Cathy E. Petry, Francesco Pierfederici, Stephen Pietrowicz, Rob Pike, Philip A. Pinto, Raymond Plante, Stephen Plate, Joel P. Plutchak, Paul A. Price, Michael Prouza, Veljko Radeka, Jayadev Rajagopal, Andrew P. Rasmussen, Nicolas Regnault, Kevin A. Reil, David J. Reiss, Michael A. Reuter, Stephen T. Ridgway, Vincent J. Riot, Steve Ritz, Sean Robinson, William Roby, Aaron Roodman, Wayne Rosing, Cecille Roucelle, Matthew R. Rumore, Stefano Russo, Abhijit Saha, Benoit Sassolas, Terry L. Schalk, Pim Schellart, Rafe H. Schindler, Samuel Schmidt, Donald P. Schneider, Michael D. Schneider, William Schoening, German Schumacher, Megan E. Schwamb, Jacques Sebag, Brian Selvy, Glenn H. Sembroski, Lynn G. Seppala, Andrew Serio, Eduardo Serrano, Richard A. Shaw, Ian Shipsey, Jonathan Sick, Nicole Silvestri, Colin T. Slater, J. Allyn Smith, R. Chris Smith, Shahram Sobhani, Christine Soldahl, Lisa Storrie-Lombardi, Edward Stover, Michael A. Strauss, Rachel A. Street, Christopher W. Stubbs, Ian S. Sullivan, Donald Sweeney, John D. Swinbank, Alexander Szalay, Peter Takacs, Stephen A. Tether, Jon J. Thaler, John Gregg Thayer, Sandrine Thomas, Adam J. Thornton, Vaikunth Thukral, Jeffrey Tice, David E. Trilling, Max Turri, Richard Van Berg, Daniel Vanden Berk, Kurt Vetter, Francoise Virieux, Tomislav Vucina, William Wahl, Lucianne Walkowicz, Brian Walsh, Christopher W. Walter, Daniel L. Wang, Shin-Yawn Wang, Michael Warner, Oliver Wiecha, Beth Willman, Scott E. Winters, David Wittman, Sidney C. Wolff, W. Michael Wood-Vasey, Xiuqin Wu, Bo Xin, Peter Yoachim, Hu Zhan, Laboratoire de l'Accélérateur Linéaire (LAL), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Université Paris Diderot - Paris 7 (UPD7), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Laboratoire des matériaux avancés (LMA), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique de Clermont (LPC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Centre de Calcul de l'IN2P3 (CC-IN2P3), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Instituto de RadioAstronomía Milimétrica (IRAM), Centre National de la Recherche Scientifique (CNRS), LSST, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Clermont Auvergne (UCA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Aix Marseille Université (AMU), Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2)

Subjects
010504 meteorology & atmospheric sciences, Astronomy, observational [methods], Field of view, Astrophysics, 7. Clean energy, 01 natural sciences, law.invention, law, size distribution, sagittarius dwarf galaxy, 010303 astronomy & astrophysics, stars: general, media_common, Physics, Reference design, general [stars], gamma-ray bursts, Astrophysics (astro-ph), observations [cosmology], proper motion stars, ia supernovae, astrometry, methods: observational, Astronomical and Space Sciences, Physical Chemistry (incl. Structural), Milky Way, media_common.quotation_subject, Dark matter, FOS: Physical sciences, Large Synoptic Survey Telescope, Astronomy & Astrophysics, milky-way tomography, Primary mirror, Telescope, surveys, astro-ph, 0103 physical sciences, Galaxy: general, general [Galaxy], 0105 earth and related environmental sciences, dark-energy constraints, Organic Chemistry, Astronomy and Astrophysics, Space and Planetary Science, Sky, tidal disruption events, cosmology: observations, digital sky survey, lensing power spectrum, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

(Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg$^2$ field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5$\sigma$ point-source depth in a single visit in $r$ will be $\sim 24.5$ (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg$^2$ with $\delta, Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overview

Published
2019
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39. Optimization of Lead-free Organic–inorganic Tin(II) Halide Perovskite Semiconductors by Scanning Electrochemical Microscopy

Author

Hsien-Yi Hsu, Minshu Du, Li Ji, Edward T. Yu, Allen J. Bard, and Ji Zhao

Subjects
General Chemical Engineering, Inorganic chemistry, Photoelectrochemistry, chemistry.chemical_element, Halide, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Electrochemistry, 01 natural sciences, Benzoquinone, 0104 chemical sciences, law.invention, Scanning electrochemical microscopy, chemistry, law, Solar cell, 0210 nano-technology, Tin, Perovskite (structure)
Abstract

Lead-free organic-inorganic tin halide perovskites were prepared and investigated by a rapid screening technique utilizing a modified scanning electrochemical microscope (SECM). We studied liquid junction photoelectrochemical (PEC) solar cells based on p-type methylammonium tin halide (MASnI3-xBrx) perovskites employing the benzoquinone (BQ) redox couple, BQ/BQ −, in dichloromethane (CH2Cl2). We found that the optimized Sn-based mixed halide perovskite, MASnI0.5Br2.5, exhibits enhanced performance and stability in liquid-junction PEC solar cells, with a power conversion efficiency of 1.51% (an increase of 20.8%) and a photovoltaic lifetime of 175 min (an increase of 75.0%), in comparison to MASnI3 perovskites.

Published
2016
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40. Mechanism of the Br − /Br 2 Redox Reaction on Platinum and Glassy Carbon Electrodes in Nitrobenzene by Cyclic Voltammetry

Author

Jinho Chang, Allen J. Bard, and Brent Bennett

Subjects
Reaction mechanism, Chemistry, General Chemical Engineering, Inorganic chemistry, chemistry.chemical_element, 02 engineering and technology, Glassy carbon, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Chemical reaction, Redox, 0104 chemical sciences, Chemical kinetics, Reaction rate constant, Electrochemistry, Cyclic voltammetry, 0210 nano-technology, Platinum
Abstract

We report the determination of a complete mechanism for the Br − /Br 2 reaction in nitrobenzene using simulations of cyclic voltammograms at platinum and glassy carbon macroelectrodes and platinum ultramicroelectrodes at varying scan rates (0.02–500 V/s) and concentrations of Br − , Br 3 − , and Br 2 (2.5–20 mM). As in other nonaqueous solvents and ionic liquids, we observe two consecutive redox processes at lower and higher potentials that we assign to the Br − /Br 3 − and Br 3 − /Br 2 redox reactions, respectively. A complete reaction mechanism, including the elementary steps of each process, was fit to the voltammetric data using DigiElch ® simulation software. The model proposed here is different from previous models of halide reactions in nonaqueous solvents in three ways. First, it proposes the direct oxidation and reduction of Br 3 − , whereas previous models describe the reduction and oxidation of X 3 − as a CE process, with the dissociation of X 3 − into X − and X 2 occurring first. Second, it is able to accurately match data at a wide range of scan rates and concentrations without the use of unrealistically large homogeneous rate constants. Finally, it can match data at platinum and glassy carbon electrodes by simply changing the apparent heterogeneous kinetics of the electron transfer reactions.

Published
2016
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41. Advanced Electrochemistry of Individual Metal Clusters Electrodeposited Atom by Atom to Nanometer by Nanometer

Author

Jiyeon Kim, Allen J. Bard, and Jeffrey E. Dick

Subjects
Materials science, Nucleation, Nanoparticle, Nanotechnology, 02 engineering and technology, General Medicine, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Electrocatalyst, Electrochemistry, 01 natural sciences, 0104 chemical sciences, Catalysis, Atom, Cluster (physics), Nanometre, 0210 nano-technology
Abstract

Metal clusters are very important as building blocks for nanoparticles (NPs) for electrocatalysis and electroanalysis in both fundamental and applied electrochemistry. Attention has been given to understanding of traditional nucleation and growth of metal clusters and to their catalytic activities for various electrochemical applications in energy harvesting as well as analytical sensing. Importantly, understanding the properties of these clusters, primarily the relationship between catalysis and morphology, is required to optimize catalytic function. This has been difficult due to the heterogeneities in the size, shape, and surface properties. Thus, methods that address these issues are necessary to begin understanding the reactivity of individual catalytic centers as opposed to ensemble measurements, where the effect of size and morphology on the catalysis is averaged out in the measurement. This Account introduces our advanced electrochemical approaches to focus on each isolated metal cluster, where we electrochemically fabricated clusters or NPs atom by atom to nanometer by nanometer and explored their electrochemistry for their kinetic and catalytic behavior. Such approaches expand the dimensions of analysis, to include the electrochemistry of (1) a discrete atomic cluster, (2) solely a single NP, or (3) individual NPs in the ensemble sample. Specifically, we studied the electrocatalysis of atomic metal clusters as a nascent electrocatalyst via direct electrodeposition on carbon ultramicroelectrode (C UME) in a femtomolar metal ion precursor. In addition, we developed tunneling ultramicroelectrodes (TUMEs) to study electron transfer (ET) kinetics of a redox probe at a single metal NP electrodeposited on this TUME. Owing to the small dimension of a NP as an active area of a TUME, extremely high mass transfer conditions yielded a remarkably high standard ET rate constant, k

Published
2016
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42. Millisecond Coulometry via Zeptoliter Droplet Collisions on an Ultramicroelectrode

Author

Allen J. Bard, Lauren M. Strawsine, Estelle Lebègue, and Jeffrey E. Dick

Subjects
Electrolysis, Chemistry, Dispersity, Analytical chemistry, Ultramicroelectrode, 02 engineering and technology, Electron, 010402 general chemistry, 021001 nanoscience & nanotechnology, Electrochemistry, 01 natural sciences, 0104 chemical sciences, Analytical Chemistry, law.invention, Coulometry, chemistry.chemical_compound, law, 0210 nano-technology, Stoichiometry, Tetrathiafulvalene
Abstract

We show that discrete collisions of zeptoliter emulsion droplets on an ultramicroelectrode (UME) can be used as individual controlled potential coulometry experiments, lasting between 100 and 500 milliseconds. By loading a highly hydrophobic toluene droplet with a hydrophobic analyte of interest and knowing the volume of the droplet to a high degree of precision, Faraday’s Law can be employed to calculate the number of electrons passed during the electrolysis. Monodisperse (±15 % of the average size) emulsion systems were created by ultrasonication followed by filtering through a 200 nm porous filter. Discrete droplet collision events were observed in the amperometric i-t curve. Each of these collisions are interpreted as individual coulometry experiments, implying that several bulk electrolyses can be carried out over the course of one collision experiment. Herein, we show calculations of the electron stoichiometry for the ferrocene oxidation reaction, which agrees well with the expected value of 1 electron. We further extend the methodology to more complicated systems, such as the oxidation of tetrathiafulvalene (TTF), tertiary aliphatic amines, such as tripropylamine (TPrA), and a 1,2-diphenylhydrazine (DPH) molecule. This electroanalytical methodology allows for fast, nanoscale electrolysis in low dielectric media.

Published
2016
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43. Optimization of PbI2/MAPbI3 Perovskite Composites by Scanning Electrochemical Microscopy

Author

Edward T. Yu, Li Ji, Ji Zhao, Allen J. Bard, Minshu Du, and Hsien-Yi Hsu

Subjects
Photocurrent, Microscope, Materials science, Annealing (metallurgy), Analytical chemistry, Quantum yield, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, law.invention, Scanning electrochemical microscopy, General Energy, law, Electrode, Irradiation, Physical and Theoretical Chemistry, Composite material, 0210 nano-technology, Perovskite (structure)
Abstract

A variety of PbI2/MAPbI3 perovskites were prepared and investigated by a rapid screening technique utilizing a modified scanning electrochemical microscope (SECM) in order to determine how excess PbI2 affects its photoelectrochemical (PEC) properties. An optimum ratio of 2.5% PbI2/MAPbI3 was found to enhance photocurrent over pristine MAPbI3 on a spot array electrode under irradiation. With bulk films of various PbI2/MAPbI3 composites prepared by a spin-coating technique of mixed precursors and a one-step annealing process, the 2.5% PbI2/MAPbI3 produced an increased photocurrent density compared to pristine MAPbI3 for 2 mM benzoquinone (BQ) reduction at −0.4 V vs Fc/Fc+. As a result of the relatively high quantum yield of MAPbI3, a time-resolved photoluminescence quenching experiment could be applied to determine electron–hole diffusion coefficients and diffusion lengths of PbI2/MAPbI3 composites, respectively. The diffusion coefficients combined with the exciton lifetime of the pristine 2.5% PbI2/MAPbI3 ...

Published
2016
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44. Probing Ion Transfer across Liquid–Liquid Interfaces by Monitoring Collisions of Single Femtoliter Oil Droplets on Ultramicroelectrodes

Author

Allen J. Bard, Udo Kragl, Steven H. Strauss, Jeffrey E. Dick, Haiqiang Deng, and Sina Kummer

Subjects
Chemistry, Supporting electrolyte, Analytical chemistry, Femtoliter, Ultramicroelectrode, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Analytical Chemistry, chemistry.chemical_compound, Electron transfer, Oil droplet, Phase (matter), Ionic liquid, 0210 nano-technology, Rubrene
Abstract

We describe a method of observing collisions of single femtoliter (fL) oil (i.e., toluene) droplets that are dispersed in water on an ultramicroelectrode (UME) to probe the ion transfer across the oil/water interface. The oil-in-water emulsion was stabilized by an ionic liquid, in which the oil droplet trapped a highly hydrophobic redox probe, rubrene. The ionic liquid also functions as the supporting electrolyte in toluene. When the potential of the UME was biased such that rubrene oxidation would be possible when a droplet collided with the electrode, no current spikes were observed. This implies that the rubrene radical cation is not hydrophilic enough to transfer into the aqueous phase. We show that current spikes are observed when tetrabutylammonium trifluoromethanesulfonate or tetrahexylammonium hexafluorophosphate are introduced into the toluene phase and when tetrabutylammonium perchlorate is introduced into the water phase, implying that the ion transfer facilitates electron transfer in the droplet collisions. The current (i)-time (t) behavior was evaluated quantitatively, which indicated the ion transfer is fast and reversible. Furthermore, the size of these emulsion droplets can also be calculated from the electrochemical collision. We further investigated the potential dependence on the electrochemical collision response in the presence of tetrabutylammonium trifluoromethanesulfonate in toluene to obtain the formal ion transfer potential of tetrabutylammonium across the toluene/water interface, which was determined to be 0.754 V in the inner potential scale. The results yield new physical insights into the charge balance mechanism in emulsion droplet collisions and indicate that the electrochemical collision technique can be used to probe formal ion transfer potentials between water and solvents with very low (ε5) dielectric constants.

Published
2016
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45. Electrocatalytic Activity of Individual Pt Nanoparticles Studied by Nanoscale Scanning Electrochemical Microscopy

Author

Allen J. Bard, Christophe Renault, Jiyeon Kim, Kevin C. Leonard, Nikoloz Nioradze, and Netzahualcóyotl Arroyo-Currás

Subjects
Chemistry, Nucleation, Nanoparticle, Nanotechnology, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Biochemistry, Catalysis, 0104 chemical sciences, Scanning electrochemical microscopy, Colloid and Surface Chemistry, Molecule, Reactivity (chemistry), Graphite, 0210 nano-technology, Nanoscopic scale
Abstract

Understanding the relationship between the structure and the reactivity of catalytic metal nanoparticles (NPs) is important to achieve higher efficiencies in electrocatalytic devices. A big challenge remains, however, in studying these relations at the individual NP level. To address this challenge, we developed an approach using nanometer-scale scanning electrochemical microscopy (SECM) for the study of the geometric property and catalytic activity of individual Pt NPs in the hydrogen oxidation reaction (HOR). Herein, Pt NPs with a few tens to a hundred nm radius were directly electrodeposited on a highly oriented pyrolitic graphite (HOPG) surface via nucleation and growth without the necessity of capping agents or anchoring molecules. A well-defined nanometer-sized tip comparable to the dimensions of the NPs and a stable nanogap between the tip and NPs enabled us to achieve lateral and vertical spatial resolutions at a nanometer-scale and study fast electron-transfer kinetics. Specifically, the use of t...

Published
2016
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46. Kinetic Study of Hydrogen Evolution Reaction over Strained MoS2 with Sulfur Vacancies Using Scanning Electrochemical Microscopy

Author

Eric Pop, Yoshio Nishi, Minshu Du, Allen J. Bard, Michal J. Mleczko, Ai Leen Koh, Hong Li, and Xiaolin Zheng

Subjects
Kinetics, chemistry.chemical_element, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Biochemistry, Sulfur, Catalysis, 0104 chemical sciences, chemistry.chemical_compound, Scanning electrochemical microscopy, Crystallography, Colloid and Surface Chemistry, Reaction rate constant, chemistry, Vacancy defect, Monolayer, 0210 nano-technology, Platinum, Molybdenum disulfide
Abstract

Molybdenum disulfide (MoS2), with its active edge sites, is a proposed alternative to platinum for catalyzing the hydrogen evolution reaction (HER). Recently, the inert basal plane of MoS2 was successfully activated and optimized with excellent intrinsic HER activity by creating and further straining sulfur (S) vacancies. Nevertheless, little is known about the HER kinetics of those S vacancies and the additional effects from elastic tensile strain. Herein, scanning electrochemical microscopy was used to determine the HER kinetic data for both unstrained S vacancies (formal potential Ev0 = −0.53 VAg/AgCl, electron-transfer coefficient αv = 0.4, electron-transfer rate constant kv0 = 2.3 × 10(–4) cm/s) and strained S vacancies (Esv0= −0.53 VAg/AgCl, αsv = 0.4, ksv0 = 1.0 × 10(–3) cm/s) on the basal plane of MoS2 monolayers, and the strained S vacancy has an electron-transfer rate 4 times higher than that of the unstrained S vacancy. This study provides a general platform for measuring the kinetics of two-dimensional material-based catalysts.

Published
2016
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47. Application of the Koutecký-Levich Method to the Analysis of Steady State Voltammograms with Ultramicroelectrodes

Author

Jiyeon Kim and Allen J. Bard

Subjects
Steady state, Chemistry, Analytical chemistry, Thermodynamics, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Electrochemistry, Kinetic energy, 01 natural sciences, Redox, 0104 chemical sciences, Analytical Chemistry, Electron transfer, Mass transfer, Rotating disk electrode, 0210 nano-technology, Current density
Abstract

We demonstrate a new experimental approach to measure heterogeneous electron transfer rates. We adapted the classical Koutecký-Levich model for a rotating disk electrode (RDE) to a general heterogeneous electrochemical kinetic study with ultramicroelectrodes (UMEs) even for fast redox systems, where different sizes of UMEs are used to modulate the mass transfer rate (m). Subsequently, a linear plot of (1/current density) vs 1/m at different potentials can be created from the obtained steady state voltammograms, which is analogous to the traditional Koutecký-Levich plot. A simple numerical treatment with a slope and y-intercept from a linear plot allows for extracting kinetic parameters. A unifying treatment is presented for the steady state quasi-reversible, irreversible, and reversible voltammograms for a simple electron transfer reaction at UMEs. This new experimental approach with submicrometer to ∼ micrometer sized UMEs exceeds the mass transfer rates achieved by conventional electrochemical methods using rotating electrodes or solely tens of micrometer sized electrodes, thus enables us to study much faster heterogeneous electron transfer kinetics with simple instrumentation. The method should be particularly useful in studying particle size and structure effects.

Published
2016
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48. Electrodeposition of Photoactive Silicon Films for Low-Cost Solar Cells

Author

Taeho Lim, Huayi Yin, Hsien-Yi Hsu, Ji Zhao, Hongwei Xie, Fardad Forouzan, and Allen J. Bard

Subjects
Materials science, Silicon, Renewable Energy, Sustainability and the Environment, business.industry, chemistry.chemical_element, 02 engineering and technology, Quantum dot solar cell, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Polymer solar cell, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Monocrystalline silicon, chemistry, Materials Chemistry, Electrochemistry, Optoelectronics, 0210 nano-technology, business
Published
2016
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49. Electrochemical Characterization of Bromine Reduction to Tribromide in Individual Nitrobenzene-in-Water Emulsion Droplets

Author

Liang Chang and A. J. Bard

Subjects
Materials science, Renewable Energy, Sustainability and the Environment, Supporting electrolyte, 020209 energy, Diffusion, Analytical chemistry, 02 engineering and technology, Chronoamperometry, Condensed Matter Physics, Electrochemistry, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Nitrobenzene, chemistry.chemical_compound, chemistry, Ionic liquid, 0202 electrical engineering, electronic engineering, information engineering, Materials Chemistry, Bulk electrolysis, Tribromide
Abstract

We report an electrochemical study of bromine reduction to tribromide in a single nitrobenzene (NB) droplet during a single collision event. The feasibility of this study is based on the favorable distribution of Br2 in NB rather than in water, which was demonstrated by voltammetry at the NB/water interface. The NB-in-water emulsions containing the ionic liquids trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)amide (ILPA) as the supporting electrolyte and sodium dodecyl sulfate (SDS) as the surfactant were prepared by a high-power ultrasonication. Its single droplet as an attoliter reactor, colliding on a 25 μm Pt UME, was monitored by chronoamperometry. The spike-type current transients of Br2 reduction can elucidate the size and size distribution of NB, and measure the diffusion in the droplet as analyzed by a bulk electrolysis model. The frequency of collisions can provide diffusion coefficient of the droplets to the UME. Moreover, the i-t decay behavior can be simulated, which fits well with the experimental one.

Published
2020
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50. Extraordinary Dielectric Properties at Heterojunctions of Amorphous Ferroelectrics

Author

Allen J. Bard, J. C. R. E. Oliveira, Andrew J. Murchison, M. Helena Braga, Tianhan Kai, and John B. Goodenough

Subjects
Chemistry, Analytical chemistry, Heterojunction, 02 engineering and technology, General Chemistry, Dielectric, Electrolyte, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Biochemistry, Ferroelectricity, Catalysis, 0104 chemical sciences, Amorphous solid, law.invention, Capacitor, Colloid and Surface Chemistry, law, Cyclic voltammetry, 0210 nano-technology, Polarization (electrochemistry)
Abstract

Materials having a high dielectric constant are needed for a variety of electrical applications from transistors to capacitors. Ferroelectric amorphous-oxide (glass) alkali-ion electrolytes of composition A2.99Ba0.005ClO (A = Li, Na) are shown by two different types of measurement and different consistent analyses to have extraordinarily high dielectric constants, varying from 109 at 25 °C to 1010 at 220 °C if the glass is properly conditioned. These anomalously high dielectric properties coexist with alkali-ion conductivities at 25 °C that are equivalent to those of the best organic-liquid electrolytes of a Li-ion cell, and cyclic voltammetry (CV) in a Au/glass electrolyte/Au cell is stable from −10 to +10 V. A model to interpret microscopically all the key features of the CV curves shows that the electric-double-layer capacitors that form at the gold/electrolyte interfaces in the Au/glass electrolyte/Au heterojunction reverse polarization at an applied voltage V = ±2.1 V, resulting in three almost equiv...

Published
2018

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