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1. Halide Perovskite High-k Field Effect Transistors with Dynamically Reconfigurable Ambipolarity

Author

Boubacar Traoré, Aditya D. Mohite, Gary McCuistian, Bruce W. Alphenaar, Sergei Tretiak, Hugo Bellezza, Nicolo Zagni, Fangze Liu, Jared Crochet, Mercouri G. Kanatzidis, Kasun Fernando, Claudine Katan, Régis Rogel, Noelia Devesa Canicoba, Jacky Even, Muhammad Ashraf Alam, Jean-Christophe Blancon, Wanyi Nie, Laurent Le Brizoual, Hsinhan Tsai, Los Alamos National Laboratory (LANL), Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Purdue University [West Lafayette], Rice University [Houston], Institut des Fonctions Optiques pour les Technologies de l'informatiON (Institut FOTON), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Chimiques de Rennes (ISCR), 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), Northwestern University [Evanston], University of Louisville, DE-FOA-0002022-1652, Office of Energy Efficiency and Renewable Energy, Laboratory Directed Research and Development, SC0012541, Office of Science, Institut Universitaire de France, CBET-1512106, Division of Chemical, Bioengineering, Environmental, and Transport Systems, Rice University, Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-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)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), 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), Université de Nantes (UN)-Université de Rennes 1 (UR1), École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-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)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-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
[PHYS]Physics [physics], Materials science, business.industry, Ambipolar diffusion, General Chemical Engineering, Biomedical Engineering, Halide, 02 engineering and technology, Dielectric, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Hysteresis, Modulation, [CHIM]Chemical Sciences, Optoelectronics, General Materials Science, Field-effect transistor, 0210 nano-technology, business, High-κ dielectric, Perovskite (structure)
Abstract

International audience; Despite the remarkable optoelectronic properties of halide perovskites, achieving reproducible field effect transistor (FET) action in polycrystalline films at room temperature has been challenging and represents a fundamental bottleneck for understanding electronic charge transport in these materials. In this work, we report halide perovskite-based FET operation at room temperature with negligible hysteresis. Extensive measurements and device modeling reveal that incorporating high-k dielectrics enables modulation of the channel conductance. Furthermore, continuous bias cycling or resting allows dynamical reconfiguration of the FETs between p-type behavior and ambipolar FET with balanced electron and hole transport and an ON/OFF ratio up to 104 and negligible degradation in transport characteristics over 100 cycles. These results elucidate the path for achieving gate modulation in perovskite thin-films and provide a platform to understand the interplay between the perovskite structure, and external stimuli such as photons, fields and functional substrates, which will lead to novel and emergent properties.

Published
2019
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2. Giant Enhancement of Photoluminescence Emission in WS2-Two-Dimensional Perovskite Heterostructures

Author

Jared Crochet, Harry A. Atwater, Aditya D. Mohite, Jean-Christophe Blancon, Tony Low, Ellen Yan, Hao Zhang, Joeson Wong, Mercouri G. Kanatzidis, Deep Jariwala, Yi Rung Lin, Arky Yang, and Wei Jiang

Subjects
Photoluminescence, Fabrication, Materials science, business.industry, Mechanical Engineering, Bioengineering, Heterojunction, 02 engineering and technology, General Chemistry, Electronic structure, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Transition metal, Optoelectronics, General Materials Science, 0210 nano-technology, business, Electronic band structure, Order of magnitude, Perovskite (structure)
Abstract

Transition metal dichalcogenides (TMDCs) and two-dimensional organic and inorganic hybrid lead halide perovskites (2DPVSKs) have emerged as highly promising materials for ultralight and ultrathin optoelectronics application. They both exhibit tunability of electronic properties such as band structure, and they can form heterostructures with various types of two-dimensional materials for novel physical properties not observed in single components. However, TMDCs exhibit poor emission efficiency due to defect states and direct-to-indirect interband transition, and 2DPVSKs suffer from poor stability in ambient atmosphere. Here we report that fabrication of TMDC-on-2DPVSK heterostructures using a solvent-free process leads to novel optical transitions unique to the heterostructure which arise from the hybrid interface and exhibit a strong photoluminescence. Moreover, a two orders of magnitude enhancement of the photoluminescence as compared to WS2 emission is observed. The TMDC on top of 2DPVSK also significantly improves the stability as compared to bare 2DPVSK. Enhanced emission can be explained by electronic structure modification of TMDC by novel interfacial interactions between TMDC and 2DPVSK materials, which shows promise of the heterostructure for high efficiency and stable optoelectronic devices.

Published
2019
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3. Highly efficient photoelectric effect in halide perovskites for regenerative electron sources

Author

Jared Crochet, Vitaly Pavlenko, Mark A. Hoffbauer, Amanda Neukirch, Sina G. Lewis, Sergei Tretiak, Siraj Sidhik, Jacky Even, Aditya D. Mohite, Jean-Christophe Blancon, Fangze Liu, Nathan A. Moody, Wanyi Nie, Hsinhan Tsai, Mercouri G. Kanatzidis, Pulickel M. Ajayan, Los Alamos National Laboratory (LANL), Rice University [Houston], Institut des Fonctions Optiques pour les Technologies de l'informatiON (Institut FOTON), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-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)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Northwestern University [Evanston], Argonne National Laboratory [Lemont] (ANL), The work at Rice University was supported by ARO STIR project N-mensional interfaces, grant W911NF-19-1-0353. The work at Los Alamos National Laboratory (LANL) was supported by the LANL Laboratory Directed Research and Development Funds (LDRD) program. This work was done in part at the Center for Nonlinear Studies (CNLS) and the Center for Integrated Nanotechnologies (CINT), a U.S. Department of Energy and Office of Basic Energy Sciences user facility, at LANL. This research used resources provided by the LANL Institutional Computing Program. Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of the U.S. Department of Energy (Contract No. 89233218NCA000001). J.E. acknowledges the financial support from the Institut Universitaire de France. Work at Northwestern was supported by the U.S. Department of Energy, Office of Science (Grant No. SC0012541, structure characterization)., 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)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials for devices, Photomultiplier, Materials science, Band gap, Science, General Physics and Astronomy, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, 7. Clean energy, Article, General Biochemistry, Genetics and Molecular Biology, Night vision, [CHIM]Chemical Sciences, Thin film, [PHYS]Physics [physics], Multidisciplinary, business.industry, Electronics, photonics and device physics, General Chemistry, Photoelectric effect, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Semiconductor, Semiconductors, Optoelectronics, Quantum efficiency, Vacuum level, 0210 nano-technology, business
Abstract

Electron sources are a critical component in a wide range of applications such as electron-beam accelerator facilities, photomultipliers, and image intensifiers for night vision. We report efficient, regenerative and low-cost electron sources based on solution-processed halide perovskites thin films when they are excited with light with energy equal to or above their bandgap. We measure a quantum efficiency up to 2.2% and a lifetime of more than 25 h. Importantly, even after degradation, the electron emission can be completely regenerated to its maximum efficiency by deposition of a monolayer of Cs. The electron emission from halide perovskites can be tuned over the visible and ultraviolet spectrum, and operates at vacuum levels with pressures at least two-orders higher than in state-of-the-art semiconductor electron sources., Electron sources play as important component in a wide range of applications. Here, the authors demonstrate efficient, regenerative, and low-cost electron sources based on solution-processed halide perovskite thin films with quantum efficiency up to 2.2% and a lifetime of more than 25 h.

Published
2021
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4. Scaling law for excitons in 2D perovskite quantum wells

Author

Aditya D. Mohite, Jared Crochet, Claudine Katan, G. T. Noe, Mikael Kepenekian, Hsinhan Tsai, Fumiya Katsutani, Sergei Tretiak, Boubacar Traore, Constantinos C. Stoumpos, Mercouri G. Kanatzidis, Andreas V. Stier, Scott A. Crooker, Laurent Pedesseau, Wanyi Nie, Junichiro Kono, Jacky Even, Jean-Christophe Blancon, Los Alamos National Laboratory ( LANL ), Rice University [Houston], Northwestern University [Evanston], Institut des Sciences Chimiques de Rennes ( ISCR ), Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Ecole Nationale Supérieure de Chimie de Rennes-Institut National des Sciences Appliquées ( INSA ) -Centre National de la Recherche Scientifique ( CNRS ), Fonctions Optiques pour les Technologies de l'informatiON ( FOTON ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Institut National des Sciences Appliquées - Rennes ( INSA Rennes ) -École Nationale Supérieure des Sciences Appliquées et de Technologie ( ENSSAT ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Bretagne Loire ( UBL ) -IMT Atlantique Bretagne-Pays de la Loire ( IMT Atlantique ), ANR-15-CE05-0018-01,TRANSHYPERO, Los Alamos National Laboratory (LANL), 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), Institut des Fonctions Optiques pour les Technologies de l'informatiON (Institut FOTON), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-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)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), ANR-15-CE05-0018,TRANSHYPERO,Vers une compréhension des propriétés de transport électronique des cellules solaires basées sur les pérovskites hybrides(2015), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), 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), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Exciton, Science, Binding energy, General Physics and Astronomy, Physics::Optics, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, [ CHIM ] Chemical Sciences, Article, General Biochemistry, Genetics and Molecular Biology, Condensed Matter::Materials Science, [CHIM]Chemical Sciences, lcsh:Science, Spectroscopy, Scaling, Quantum well, Perovskite (structure), [PHYS]Physics [physics], Condensed Matter::Quantum Gases, Multidisciplinary, [ PHYS ] Physics [physics], Condensed matter physics, Condensed Matter::Other, business.industry, General Chemistry, Reduced mass, 021001 nanoscience & nanotechnology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 0104 chemical sciences, Semiconductor, lcsh:Q, Condensed Matter::Strongly Correlated Electrons, 0210 nano-technology, business
Abstract

Ruddlesden–Popper halide perovskites are 2D solution-processed quantum wells with a general formula A2A’n-1MnX3n+1, where optoelectronic properties can be tuned by varying the perovskite layer thickness (n-value), and have recently emerged as efficient semiconductors with technologically relevant stability. However, fundamental questions concerning the nature of optical resonances (excitons or free carriers) and the exciton reduced mass, and their scaling with quantum well thickness, which are critical for designing efficient optoelectronic devices, remain unresolved. Here, using optical spectroscopy and 60-Tesla magneto-absorption supported by modeling, we unambiguously demonstrate that the optical resonances arise from tightly bound excitons with both exciton reduced masses and binding energies decreasing, respectively, from 0.221 m0 to 0.186 m0 and from 470 meV to 125 meV with increasing thickness from n equals 1 to 5. Based on this study we propose a general scaling law to determine the binding energy of excitons in perovskite quantum wells of any layer thickness., Hybrid 2D layered perovskites are solution-processed quantum wells whose optoelectronic properties are tunable by varying the thickness of the inorganic slab. Here Blancon et al. work out a general behavior for dependence of the excitonic properties in layered 2D perovskites.

Published
2018
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5. Cation Alloying Delocalizes Polarons in Lead-halide Perovskites

Author

Jared Crochet, Laurent Pedesseau, Liujiang Zhou, Sergei Tretiak, Amanda Neukirch, Claudine Katan, Wanyi Nie, Hsinhan Tsai, Jacky Even, Aditya D. Mohite, Los Alamos National Laboratory (LANL), University of Electronic Science and Technology of China [Chengdu] (UESTC), Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), 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), Institut des Fonctions Optiques pour les Technologies de l'informatiON (Institut FOTON), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS), Rice University [Houston], Agence Nationale de la Recherche, Laboratory Directed Research and Development, Institut Universitaire de France, ANR-15-CE05-0018,TRANSHYPERO,Vers une compréhension des propriétés de transport électronique des cellules solaires basées sur les pérovskites hybrides(2015), University of Electronic Science and Technology of China (UESTC), 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), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-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)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), and Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)

Subjects
[PHYS]Physics [physics], Materials science, Band gap, Binding energy, 02 engineering and technology, Crystal structure, 010402 general chemistry, 021001 nanoscience & nanotechnology, Polaron, 01 natural sciences, 0104 chemical sciences, Delocalized electron, Formamidinium, Chemical physics, First principle, [CHIM]Chemical Sciences, General Materials Science, Physical and Theoretical Chemistry, 0210 nano-technology, Perovskite (structure)
Abstract

International audience; Recently, mixed-cation perovskites have promised enhanced performances concerning stability and efficiency in optoelectronic devices. Here, we report a systematic study on the effects of cation alloying on polaronic properties in cation-alloyed perovskites using first principle calculations. We find that cation alloying significantly reduces the polaron binding energies for both electrons and holes compared to pure methylammonium lead iodide (MAPbI3). This is rationalized in terms of crystal symmetry reduction that causes polarons to be more delocalized. Electron polarons undergo large Jahn-Teller distortions (~15−30%) while hole polarons tend to shrink lattice by ~5%. Such different lattice distortion footprints could be utilized to distinguish the type of polarons. Finally, our simulations show that a Cs, formamidinium (FA) and MA mixture can effectively minimize polaron binding energy while weakly affecting band gap, in a good agreement with experimental findings. These modeling results can guide future development of halide perovskite materials compositions for optoelectronic applications.

Published
2019
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6. Estimation of full‐field, full‐order experimental modal model of cable vibration from digital video measurements with physics‐guided unsupervised machine learning and computer vision

Author

John Bowlan, Alexander Roeder, Jared Crochet, Huiying Zhang, Lorenzo Sanchez, Yongchao Yang, Charles R. Farrar, and David Mascareñas

Subjects
business.industry, Full order, Building and Construction, Video processing, Full field, Blind signal separation, Vibration, Operational Modal Analysis, Modal, Mechanics of Materials, Unsupervised learning, Computer vision, Artificial intelligence, business, Civil and Structural Engineering
Published
2019
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7. High-efficiency two-dimensional Ruddlesden–Popper perovskite solar cells

Author

Laurent Pedesseau, Mercouri G. Kanatzidis, Jun Lou, Sergei Tretiak, Hsinhan Tsai, Jared Crochet, Pulickel M. Ajayan, Jacky Even, Aditya D. Mohite, Jean-Christophe Blancon, Gautam Gupta, Michael J. Bedzyk, Rafael Verduzco, Boris Harutyunyan, Muhammad A. Alam, Wanyi Nie, Reza Asadpour, Amanda Neukirch, Constantinos C. Stoumpos, Los Alamos National Laboratory (LANL), Rice University [Houston], Northwestern University [Evanston], Purdue University [West Lafayette], Fonctions Optiques pour les Technologies de l'informatiON (FOTON), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université européenne de Bretagne - European University of Brittany (UEB)-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)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)-Télécom Bretagne, Argonne National Laboratory [Lemont] (ANL), Université de Rennes (UR)-Université européenne de Bretagne - European University of Brittany (UEB)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Télécom Bretagne-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 7. Clean energy, 01 natural sciences, law.invention, [SPI]Engineering Sciences [physics], law, Photovoltaics, Solar cell, [CHIM]Chemical Sciences, Relative humidity, Thin film, Perovskite (structure), [PHYS]Physics [physics], Multidisciplinary, business.industry, Photovoltaic system, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Hysteresis, Degradation (geology), Optoelectronics, 0210 nano-technology, business
Abstract

International audience; Three-dimensional organic–inorganic perovskites have emerged as one of the most promising thin-film solar cell materials owing to their remarkable photophysical properties, which have led to power conversion efficiencies exceeding 20 per cent, with the prospect of further improvements towards the Shockley–Queisser limit for a single‐junction solar cell (33.5 per cent). Besides efficiency, another critical factor for photovoltaics and other optoelectronic applications is environmental stability and photostability under operating conditions. In contrast to their three-dimensional counterparts, Ruddlesden–Popper phases—layered two-dimensional perovskite films—have shown promising stability, but poor efficiency at only 4.73 per cent. This relatively poor efficiency is attributed to the inhibition of out-of-plane charge transport by the organic cations, which act like insulating spacing layers between the conducting inorganic slabs. Here we overcome this issue in layered perovskites by producing thin films of near-single-crystalline quality, in which the crystallographic planes of the inorganic perovskite component have a strongly preferential out-of-plane alignment with respect to the contacts in planar solar cells to facilitate efficient charge transport. We report a photovoltaic efficiency of 12.52 per cent with no hysteresis, and the devices exhibit greatly improved stability in comparison to their three-dimensional counterparts when subjected to light, humidity and heat stress tests. Unencapsulated two-dimensional perovskite devices retain over 60 per cent of their efficiency for over 2,250 hours under constant, standard (AM1.5G) illumination, and exhibit greater tolerance to 65 per cent relative humidity than do three-dimensional equivalents. When the devices are encapsulated, the layered devices do not show any degradation under constant AM1.5G illumination or humidity. We anticipate that these results will lead to the growth of single-crystalline, solution-processed, layered, hybrid, perovskite thin films, which are essential for high-performance opto-electronic devices with technologically relevant long-term stability.

Published
2016
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8. Ubiquity of Exciton Localization in Cryogenic Carbon Nanotubes

Author

Alexander Högele, Alexander Kneer, Jared Crochet, Jonathan Noé, and Matthias S. Hofmann

Subjects
Nanotube, Letter, Photoluminescence, Materials science, exciton localization, Exciton, Bioengineering, Nanotechnology, 02 engineering and technology, Carbon nanotube, 01 natural sciences, law.invention, Condensed Matter::Materials Science, law, 0103 physical sciences, General Materials Science, 010306 general physics, Condensed Matter::Other, Mechanical Engineering, General Chemistry, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Optical properties of carbon nanotubes, photoluminescence spectroscopy, Chemical physics, 0210 nano-technology
Abstract

We present photoluminescence studies of individual semiconducting single-wall carbon nanotubes at room and cryogenic temperatures. From the analysis of spatial and spectral features of nanotube photoluminescence, we identify characteristic signatures of unintentional exciton localization. Moreover, we quantify the energy scale of exciton localization potentials as ranging from a few to a few tens of millielectronvolts and stemming from both environmental disorder and shallow covalent side-wall defects. Our results establish disorder-induced crossover from the diffusive to the localized regime of nanotube excitons at cryogenic temperatures as a ubiquitous phenomenon in micelle-encapsulated and as-grown carbon nanotubes.

Published
2016
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9. Stable Light-Emitting Diodes Using Phase-Pure Ruddlesden-Popper Layered Perovskites

Author

Roberto Brenes, Richard H. Friend, Wanyi Nie, Vladimir Bulovic, Constantinos C. Stoumpos, Jared Crochet, Sergei Tretiak, Chan Myae Myae Soe, Samuel D. Stranks, Giovanni Azzellino, Jacky Even, Jean-Christophe Blancon, Aditya Sadhanala, Aditya D. Mohite, Mercouri G. Kanatzidis, Hsinhan Tsai, Pulickel M. Ajayan, Jinkyoung Yoo, Los Alamos National Laboratory (LANL), Rice University [Houston], Northwestern University [Evanston], Institut des Fonctions Optiques pour les Technologies de l'informatiON (Institut FOTON), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-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)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Cavendish Laboratory, University of Cambridge [UK] (CAM), Massachusetts Institute of Technology (MIT), École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-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)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), N00014-17-1-2231, Office of Naval Research, DE-AC02-06CH11357, U.S. Department of Energy, and PIOF-GA-2013-622630, Seventh Framework Programme

Subjects
Fabrication, Materials science, LEDs, 02 engineering and technology, Electroluminescence, 010402 general chemistry, 01 natural sciences, law.invention, Crystal, crystal orientation, law, Phase (matter), color tunability, [CHIM]Chemical Sciences, General Materials Science, Voltage droop, [PHYS]Physics [physics], business.industry, Mechanical Engineering, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Semiconductor, Mechanics of Materials, Optoelectronics, 0210 nano-technology, business, Voltage, Ruddlesden-Popper layered perovskites, Light-emitting diode
Abstract

International audience; State-of-the-art light emitting diodes (LEDs) are made from high-purity alloys of III-V semiconductors or small molecules, but high fabrication cost and conplicated synthetic process have limited their widespread use for large area solid-state lighting applications. Here we report efficient and stable LEDs processed from solution with tunable color enabled by using phase-pure two-dimensional (2D) Ruddlesden-Popper (RP) layered perovskites with a formula (CH3(CH2)3NH3)2(CH3NH3)n-1PbnI3n+1 (n=3-5 in this report). By using controlled vertically oriented of crystal in the thin-films that facilitate efficient charge injection and transport, we obtain efficient electroluminescence with a radiance of 35 W Sr-1 cm-2 at 744 nm with an ultra-low turn-on voltage of 1V. Finally, operational stability tests suggest that phase purity is strongly correlated to stability. Phase-pure 2D perovskites exhibit >14 hours of stable operation at peak operating conditions with no droop at current-densities of several Amperes/cm2 in comparison to mixtures of 2D/3D mixture or 3D perovskites, which degrade within minutes.

Published
2018
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10. Geometry Distortion and Small Polaron Binding Energy Changes with Ionic Substitution in Halide Perovskites

Author

Claudine Katan, Jacky Even, Hsinhan Tsai, Iwnetim Abate, Sergei Tretiak, Jared Crochet, Wanyi Nie, Liujiang Zhou, Amanda Neukirch, Laurent Pedesseau, Aditya D. Mohite, Los Alamos National Laboratory (LANL), Stanford University, Institut des Fonctions Optiques pour les Technologies de l'informatiON (Institut FOTON), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-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)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Rice University [Houston], 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), Agence Nationale de la Recherche, Laboratory Directed Research and Development, Institut Universitaire de France, ANR-15-CE05-0018,TRANSHYPERO,Vers une compréhension des propriétés de transport électronique des cellules solaires basées sur les pérovskites hybrides(2015), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS), 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
[PHYS]Physics [physics], Materials science, Binding energy, Substitution (logic), Ionic bonding, Halide, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Polaron, 01 natural sciences, 0104 chemical sciences, Chemical physics, Distortion, [CHIM]Chemical Sciences, General Materials Science, Physical and Theoretical Chemistry, 0210 nano-technology
Abstract

International audience; Halide perovskites have demonstrated remarkable performance in optoelectronic applications. Despite extraordinary progress, questions remain about device stability. We report an in-depth computational study of small polaron formation, electronic structure, charge density, and reorganization energies of several experimentally relevant halide perovskites using isolated clusters. Local lattice symmetry, electronic structure, and electron-phonon coupling are interrelated in polaron formation in these materials. To illustrate this, first principles calculations are performed on (MA/Cs/FA)Pb(I/Br)3 and MASnI3. Across the materials studied, electron small polaron formation is manifested by Jahn-Teller like distortions in the central octahedron, with apical PbI bonds expanding significantly more than the equatorial bonds. In contrast, hole polarons cause the central octahedron to uniformly contract. This difference in manifestation of electron and hole polaron formation can be a tool to determine what is taking place in individual systems to systematically control performance. Other trends as the anion and cations are changed, are established for optimization in specific optoelectronic applications.

Published
2018
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11. High-efficiency solution-processed perovskite solar cells with millimeter-scale grains

Author

Gautam Gupta, Manish Chhowalla, Jean-Christophe Blancon, Sergei Tretiak, Aditya D. Mohite, Jared Crochet, Hsing-Lin Wang, Amanda Neukirch, Reza Asadpour, Hsinhan Tsai, Wanyi Nie, and Muhammad A. Alam

Subjects
Multidisciplinary, Fabrication, business.industry, Photovoltaic system, Nanotechnology, Methylammonium lead halide, chemistry.chemical_compound, Semiconductor, chemistry, Photovoltaics, Optoelectronics, Grain boundary, Thin film, business, Perovskite (structure)
Abstract

Large-crystal perovskite films The performance of organic-inorganic hybrid perovskite planar solar cells has steadily improved. One outstanding issue is that grain boundaries and defects in polycrystalline films degrade their output. Now, two studies report the growth of millimeter-scale single crystals. Nie et al. grew continuous, pinhole-free, thin iodochloride films with a hot-casting technique and report device efficiencies of 18%. Shi et al. used antisolvent vapor-assisted crystallization to grow millimeter-scale bromide and iodide cubic crystals with charge-carrier diffusion lengths exceeding 10 mm. Science , this issue p. 522 , p. 519

Published
2015
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12. Spatially Resolved Photoexcited Charge-Carrier Dynamics in Phase-Engineered Monolayer MoS2

Author

Jared Crochet, Jun Lou, Sina Najmaei, Rajesh Kappera, Pulickel M. Ajayan, Jean-Christophe Blancon, Aditya D. Mohite, Benjamin D. Mangum, Sidong Lei, Gautam Gupta, Manish Chhowalla, and Hisato Yamaguchi

Subjects
Photocurrent, Materials science, Photoluminescence, business.industry, Schottky barrier, General Engineering, General Physics and Astronomy, Schottky diode, Chemical vapor deposition, Photoexcitation, Monolayer, Optoelectronics, General Materials Science, Charge carrier, business
Abstract

A fundamental understanding of the intrinsic optoelectronic properties of atomically thin transition-metal dichalcogenides (TMDs) is crucial for its integration into high performance semiconductor devices. Here, we investigate the transport properties of chemical vapor deposition (CVD) grown monolayer molybdenum disulfide (MoS2) under photoexcitation using correlated scanning photocurrent microscopy and photoluminescence imaging. We examined the effect of local phase transformation underneath the metal electrodes on the generation of photocurrent across the channel length with diffraction-limited spatial resolution. While maximum photocurrent generation occurs at the Schottky contacts of semiconducting (2H-phase) MoS2, after the metallic phase transformation (1T-phase), the photocurrent peak is observed toward the center of the device channel, suggesting a strong reduction of native Schottky barriers. Analysis using the bias and position dependence of the photocurrent indicates that the Schottky barrier heights are a few millielectron volts for 1T- and ∼ 200 meV for 2H-contacted devices. We also demonstrate that a reduction of native Schottky barriers in a 1T device enhances the photoresponsivity by more than 1 order of magnitude, a crucial parameter in achieving high-performance optoelectronic devices. The obtained results pave a way for the fundamental understanding of intrinsic optoelectronic properties of atomically thin TMDs where ohmic contacts are necessary for achieving high-efficiency devices with low power consumption.

Published
2015
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13. Resonance Raman signature of intertube excitons in compositionally-defined carbon nanotube bundles

Author

Jared Crochet, Andrei Piryatinski, Erik H. Haroz, Angela R. Hight Walker, Jeffrey R. Simpson, Stephen K. Doorn, Oleksiy Roslyak, Hagen Telg, and Juan G. Duque

Subjects
Nanotube, Materials science, Science, Exciton, Resonance Raman spectroscopy, General Physics and Astronomy, 02 engineering and technology, Carbon nanotube, 01 natural sciences, General Biochemistry, Genetics and Molecular Biology, Article, law.invention, Delocalized electron, symbols.namesake, Condensed Matter::Materials Science, law, 0103 physical sciences, lcsh:Science, 010306 general physics, Multidisciplinary, Condensed matter physics, Fano resonance, Resonance, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, symbols, lcsh:Q, 0210 nano-technology, Raman spectroscopy
Abstract

Electronic interactions in low-dimensional nanomaterial heterostructures can lead to novel optical responses arising from exciton delocalization over the constituent materials. Similar phenomena have been suggested to arise between closely interacting semiconducting carbon nanotubes of identical structure. Such behavior in carbon nanotubes has potential to generate new exciton physics, impact exciton transport mechanisms in nanotube networks, and place nanotubes as one-dimensional models for such behaviors in systems of higher dimensionality. Here we use resonance Raman spectroscopy to probe intertube interactions in (6,5) chirality-enriched bundles. Raman excitation profiles for the radial breathing mode and G-mode display a previously unobserved sharp resonance feature. We show the feature is evidence for creation of intertube excitons and is identified as a Fano resonance arising from the interaction between intratube and intertube excitons. The universality of the model suggests that similar Raman excitation profile features may be observed for interlayer exciton resonances in 2D multilayered systems., Bundles of single-wall carbon nanotubes with enriched chirality can be used as model systems for exploring exciton physics in low-dimensional nanostructures. Here, the authors use resonant Raman spectroscopy to probe intertube interactions in bundles of (6,5)-enriched carbon nanotubes, and observe a Fano resonance arising from coupling between intertube and intratube excitons.

Published
2017

14. Extremely efficient internal exciton dissociation through edge states in layered 2D perovskites

Author

Costas C. Stoumpos, Pulickel M. Ajayan, Mikael Kepenekian, Claudine Katan, Hsinhan Tsai, Laurent Pedesseau, Sergei Tretiak, Chan Myae Myae Soe, Aditya D. Mohite, John Jared Crochet, Jacky Even, Jean-Christophe Blancon, Wanyi Nie, Mercouri G. Kanatzidis, Matthew Y. Sfeir, Kannatassen Appavoo, Los Alamos National Laboratory (LANL), Northwestern University [Evanston], Rice University [Houston], Institut des Fonctions Optiques pour les Technologies de l'informatiON (Institut FOTON), École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-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)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-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)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Brookhaven National Laboratory [Upton, NY] (BNL), U.S. Department of Energy [Washington] (DOE)-UT-Battelle, LLC-Stony Brook University [SUNY] (SBU), State University of New York (SUNY)-State University of New York (SUNY), The work in France was supported by Cellule Energie du CNRS (SOLHYBTRANS Project) and University of Rennes 1 (Action Incitative, Défis Scientifique Emergents 2015)., CINT/LANL contract DE-AC52-06NA25396, SOLHYBTRANS, Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS), 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), UT-Battelle, LLC-Stony Brook University [SUNY] (SBU), and State University of New York (SUNY)-State University of New York (SUNY)-U.S. Department of Energy [Washington] (DOE)

Subjects
[PHYS]Physics [physics], Multidisciplinary, Condensed matter physics, Chemistry, Band gap, Exciton, 02 engineering and technology, Electronic structure, Electron, 010402 general chemistry, 021001 nanoscience & nanotechnology, 7. Clean energy, 01 natural sciences, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Condensed Matter::Materials Science, [SPI]Engineering Sciences [physics], [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], Coulomb, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Thin film, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 0210 nano-technology, Quantum well, Perovskite (structure)
Abstract

How perovskites have the edge Two-dimensional Ruddlesden-Popper perovskites form quantum wells by sandwiching inorganic-organic perovskite layers used in photovoltaic devices between organic layers. Blancon et al. show that if the perovskite layer is more than two unit cells thick, photogenerated excitons undergo an unusual but highly efficient process for creating free carriers that can be harvested in photovoltaic devices (see the Perspective by Bakr and Mohammed). Lower-energy local states at the edges of the perovskite layer facilitate dissociation into electrons and holes that are well protected from recombination. Science , this issue p. 1288 ; see also p. 1260

Published
2017
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15. Polaron stabilization by cooperative lattice distortion and cation rotations in hybrid perovskite materials

Author

Hsinhan Tsai, Amanda Neukirch, Laurent Pedesseau, Sergei Tretiak, Wanyi Nie, Jacky Even, Matthew Y. Sfeir, Gautam Gupta, Jean-Christophe Blancon, Aditya D. Mohite, Kannatassen Appavoo, Jared Crochet, Claudine Katan, Los Alamos National Laboratory (LANL), Brookhaven National Laboratory [Upton, NY] (BNL), U.S. Department of Energy [Washington] (DOE)-UT-Battelle, LLC-Stony Brook University [SUNY] (SBU), State University of New York (SUNY)-State University of New York (SUNY), 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), Fonctions Optiques pour les Technologies de l'informatiON (FOTON), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université européenne de Bretagne - European University of Brittany (UEB)-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)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Télécom Bretagne-Centre National de la Recherche Scientifique (CNRS), The work in France was supported by Cellule Energie du CNRS (SOLHYBTRANS Project) and University of Rennes 1 (Action Incitative, Défis Scientifique Emergents 2015). J.E. work was supported by the Fondation d’entreprises banque Populaire de l’Ouest under Grant PEROPHOT 2015.The work at Los Alamos National Laboratory (LANL) was supported by the LANL LDRD program (A.J.N., A.D.M, G.G., and S.T.). This work was done in part at Center for Nonlinear Studies (CNLS) and the Center for Integrated Nano- technologies CINT), a U.S. Department of Energy and Office of Basic Energy Sciences user facility, at LANL. This research used resources provided by the LANL Institutional Computing Program. LANL is operated by Los Alamos National Security, LLC, for the National Nuclear Security Administration of the U.S. Department of Energy under contract DE-AC52- 06NA25396.This research used resources of the Center for Functional Nanomaterials, which is a US DOE Office of Science Facility, at Brookhaven National Laboratory under Contract No. DE- SC0012704., Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-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)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), UT-Battelle, LLC-Stony Brook University [SUNY] (SBU), State University of New York (SUNY)-State University of New York (SUNY)-U.S. Department of Energy [Washington] (DOE), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), 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), Université de Rennes (UR)-Université européenne de Bretagne - European University of Brittany (UEB)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Télécom Bretagne-Centre National de la Recherche Scientifique (CNRS), and even, jacky

Subjects
Materials science, [SPI] Engineering Sciences [physics], Inorganic chemistry, Ionic bonding, Bioengineering, 02 engineering and technology, Electronic structure, 010402 general chemistry, Polaron, 7. Clean energy, 01 natural sciences, [PHYS] Physics [physics], photovoltaic, [SPI]Engineering Sciences [physics], [CHIM] Chemical Sciences, [CHIM]Chemical Sciences, General Materials Science, ComputingMilieux_MISCELLANEOUS, Perovskite (structure), Photocurrent, [PHYS]Physics [physics], polaron, Mechanical Engineering, Charge density, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, cation rotations, Chemical physics, Organic−inorganic perovskite, Density functional theory, Charge carrier, 0210 nano-technology
Abstract

International audience; Solution-processed organometallic perovskites have rapidly developed into a top candidate for the active layer of photovoltaic devices. Despite the remarkable progress associated with perovskite materials, many questions about the fundamental photophysical processes taking place in these devices remain open. High on the list of unexplained phenomena are very modest mobilities despite low charge carrier effective masses. Moreover, experiments elucidate unique degradation of photocurrent affecting stable operation of perovskite solar cells. These puzzles suggest that while ionic hybrid perovskite devices may have efficiencies on par with conventional Si and GaAs devices, they exhibit more complicated charge transport phenomena. Here we report the results from an in-depth computational study of small polaron formation, electronic structure, charge density, and reorganization energies using both periodic boundary conditions and isolated structures. Using the hybrid Density Functional Theory, we found that volumetric strain in a CsPbI3 cluster creates a polaron with binding energy of around 300 meV and 900 meV for holes and electrons, respectively. In the MAPbI3 (MA=CH3NH3) cluster, both volumetric strain and MA reorientation effects lead to larger binding energies at around 600 meV and 1300 meV for holes and electrons, respectively. Such large reorganization energies suggest appearance of small polarons in organometallic perovskite materials. The fact that both volumetric lattice strain and MA molecular rotational degrees of freedom can cooperate to create and stabilize polarons, indicates that in order to mitigate this problem, formamidinium (FA=HC(NH2)2) and cesium (Cs) based crystals and alloys, are potentially better materials for solar cell and other optoelectronic applications.

Published
2016
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16. The effects of electronic impurities and electron-hole recombination dynamics on large-grain organic-inorganic perovskite photovoltaic efficiencies

Author

Jean-Christophe Blancon, Gautam Gupta, Jared Crochet, Aditya D. Mohite, Laurent Cognet, Amanda Neukirch, Wanyie Nie, Sergei Tretiak, Los Alamos National Laboratory (LANL), Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université de Bordeaux (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), LP2N_A1, and LP2N_G1

Subjects
Materials science, Photoluminescence, business.industry, [PHYS.PHYS.PHYS-BIO-PH]Physics [physics]/Physics [physics]/Biological Physics [physics.bio-ph], 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, 7. Clean energy, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Biomaterials, Semiconductor, Impurity, Chemical physics, Electrochemistry, Charge carrier, Thin film, 0210 nano-technology, Spectroscopy, business, Excitation, Perovskite (structure)
Abstract

International audience; Organometallic perovskites have attracted considerable attention after promising developments in energy harvesting and other optoelectronic applications. However, further optimization will require a deeper understanding of the intrinsic photo-physics of materials with relevant structural characteristics. Here we investigate the dynamics of photogenerated charge carriers in large-area grain organometallic perovskite thin films via confocal time-resolved photoluminescence spectroscopy. It is found that the bimolecular recombination of free charges is the dominant decay mechanism at excitation densities relevant for photovoltaic applications. Bimolecular coefficients are found to be on the order of 10-9 cm3/s, comparable to typical direct-gap semiconductors, yet significantly smaller than theoretically expected. We also demonstrate that there is no degradation in carrier transport in these thin films due to electronic impurities. Suppressed electron-hole recombination and transport that is not limited by deep level defects provide a microscopic model for the superior performance of large-area grain hybrid perovskites for photovoltaic applications.

Published
2016
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17. Ultrafast Excitation Energy Transfer in Small Semiconducting Carbon Nanotube Aggregates

Author

Jared Crochet, Guglielmo Lanzani, Tobias Hertel, Giulio Cerullo, and Larry Lüer

Subjects
education.field_of_study, Materials science, Exciton, Population, General Engineering, General Physics and Astronomy, Carbon nanotube, law.invention, law, Ultrafast laser spectroscopy, General Materials Science, Atomic physics, Spectroscopy, Ground state, education, Femtochemistry, Excitation
Abstract

We study excitation energy transfer in small aggregates of chirality enriched carbon nanotubes by transient absorption spectroscopy. Ground state photobleaching is used to monitor exciton population dynamics with sub-10 fs time resolution. Upon resonant excitation of the first exciton transition in (6,5) tubes, we find evidence for energy transfer to (7,5) tubes within our time resolution (

Published
2010
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18. Intersubband Decay of 1-D Exciton Resonances in Carbon Nanotubes

Author

Vasili Perebeinos, Phaedon Avouris, Katharina Arnold, Manfred M. Kappes, Jared Crochet, and Tobias Hertel

Subjects
Condensed Matter - Materials Science, Materials science, Photoluminescence, Condensed Matter::Other, Phonon, Branching fraction, Mechanical Engineering, Exciton, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, Resonance, Bioengineering, General Chemistry, Carbon nanotube, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Condensed Matter Physics, Molecular physics, law.invention, Condensed Matter::Materials Science, law, General Materials Science, Photoluminescence excitation, Line (formation)
Abstract

We have studied intersubband decay of E22 excitons in semiconducting carbon nanotubes experimentally and theoretically. Photoluminescence excitation line widths of semiconducting nanotubes with chiral indicess (n, m) can be mapped onto a connectivity grid with curves of constant (n-m) and (2n+m). Moreover, the global behavior of E22 linewidths is best characterized by a strong increase with energy irrespective of their (n-m) mod(3)= \pm 1 family affiliation. Solution of the Bethe-Salpeter equations shows that the E22 linewidths are dominated by phonon assisted coupling to higher momentum states of the E11 and E12 exciton bands. The calculations also suggest that the branching ratio for decay into exciton bands vs free carrier bands, respectively is about 10:1., Comment: 4 pages, 4 figures

Published
2007
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19. Mechanism of electrolyte-induced brightening in single-wall carbon nanotubes

Author

Jared Crochet, Laurent Cognet, Sergei Tretiak, Juan G. Duque, Brahim Lounis, Laura Oudjedi, Stephen K. Doorn, Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory (LANL), lp2n-01,lp2n-12, Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), and Center for Integrated Nanotechnologies

Subjects
Nanotube, Photoluminescence, Luminescence, [PHYS.PHYS.PHYS-BIO-PH]Physics [physics]/Physics [physics]/Biological Physics [physics.bio-ph], Exciton, Diffusion, FOS: Physical sciences, 02 engineering and technology, Electrolyte, Carbon nanotube, 010402 general chemistry, Photochemistry, 01 natural sciences, Biochemistry, Catalysis, law.invention, Electrolytes, Colloid and Surface Chemistry, Pulmonary surfactant, law, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Condensed Matter - Materials Science, Quenching (fluorescence), Condensed Matter - Mesoscale and Nanoscale Physics, Chemistry, Nanotubes, Carbon, Materials Science (cond-mat.mtrl-sci), Sodium Dodecyl Sulfate, General Chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], 0210 nano-technology
Abstract

International audience; While addition of electrolyte to sodium dodecyl sulfate suspensions of single-wall carbon nanotubes has been demonstrated to result in significant brightening of the nanotube photoluminescence (PL), the brightening mechanism has remained unresolved. Here, we probe this mechanism using time-resolved PL decay measurements. We find that PL decay times increase by a factor of 2 on addition of CsCl as the electrolyte. Such an increase directly parallels an observed near-doubling of PL intensity, indicating the brightening results primarily from changes in nonradiative decay rates associated with exciton diffusion to quenching sites. Our findings indicate that a reduced number of these sites results from electrolyte-induced reorientation of the surfactant surface structure that partially removes pockets of water from the tube surface where excitons can dissociate, and thus underscores the contribution of interfacial water in exciton recombination processes.

Published
2013
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20. Disorder Limited Exciton Transport in Colloidal Single-Wall Carbon Nanotubes

Author

Jared Crochet, Laurent Cognet, James H. Werner, Brahim Lounis, Juan G. Duque, Stephen K. Doorn, Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory (LANL), Center for Integrated Nanotechnologies, lp2n-01,lp2n-12, Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), and Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Photoluminescence, Mean free path, Exciton, exchange interaction, Non-equilibrium thermodynamics, Bioengineering, 02 engineering and technology, Carbon nanotube, 010402 general chemistry, 01 natural sciences, law.invention, Condensed Matter::Materials Science, law, General Materials Science, carbon nanotube, Diffusion (business), Biexciton, exciton, Condensed matter physics, Chemistry, Mechanical Engineering, dephasing, General Chemistry, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Fick's laws of diffusion, 0104 chemical sciences, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], transport, 0210 nano-technology
Abstract

International audience; We present measurements of S1 exciton transport in (6,5) carbon nanotubes at room temperature in a colloidal environment. Exciton diffusion lengths associated with end quenching paired with photoluminescence lifetimes provide a direct basis for determining a median dif- fusion constant of approximately 7.5 cm2s-1. Our experimental results are compared to model diffusion constants calculated using a realistic exciton dispersion accounting for a logarithmic correction due to the exchange self-energy and a non-equilibrium distribution between bright and dark excitons. The intrinsic diffusion constant associated with acoustic phonon scattering is too large to explain the observed diffusion length, and as such, we attribute the observedtransport to disorder-limited diffusional transport associated with the dynamics of the colloidal interface. In this model an effective surface potential limits the exciton mean free path to the same size as that of the exciton wavefunction, defined by the strength of the electron-hole Coulomb interaction.

Published
2012
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21. Free-carrier generation in aggregates of single-wall carbon nanotubes by photoexcitation in the ultraviolet regime

Author

Larry Lüer, Jared Crochet, Stephen K. Doorn, Sajjad Hoseinkhani, Guglielmo Lanzani, and Tobias Hertel

Subjects
Materials science, business.industry, Graphene, Exciton, General Physics and Astronomy, Carbon nanotube, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, medicine.disease_cause, Molecular physics, Spectral line, law.invention, Photoexcitation, law, Saddle point, medicine, Optoelectronics, business, Ultraviolet, Saddle
Abstract

We present evidence for the generation of free carriers in aggregated single-wall carbon nanotubes by photoexcitation in the energetic range of the π→π(*) transition associated with the M saddle point of the graphene lattice. The underlying broad absorption culminating at 4.3 eV can be fit well with a Fano line shape that describes strong coupling of a saddle-point exciton to an underlying free electron-hole pair continuum. Moreover, it is demonstrated that transitions in this energetic region autoionize into the continuum by detecting features unique to the presence of free charges in the transient transmission spectra of the continuum-embedded second sub-band exciton, S(2).

Published
2011

22. Ultrafast exciton and charge transfer in small aggregates of carbon nanotubes

Author

Sajjad Hoseinkhani, Jared Crochet, Guglielmo Lanzani, Tobias Hertel, Giulio Cerullo, and Larry Lüer

Subjects
education.field_of_study, Materials science, Absorption spectroscopy, Exciton, Population, Carbon nanotube, law.invention, Condensed Matter::Materials Science, law, Ultrafast laser spectroscopy, Charge carrier, Density gradient ultracentrifugation, Atomic physics, education, Biexciton
Abstract

We study excitation energy and charge transfer in small aggregates of chirality enriched carbon nanotubes by transient absorption spectroscopy. Ground state photobleaching is used to monitor exciton population dynamics with sub-10 fs time resolution. Upon resonant excitation of the first exciton transition in (6,5) tubes, we find evidence for energy transfer to (7,5) tubes within our time resolution (< 10 fs). After pumping at high pump energies, free charge carriers are produced via exciton scattering into the underlying continuum bands. We obtain clearly distinguished photoinduced features in the visible spectral range, that allow for real-time tracing of charge carrier dynamics in carbon nanotubes on a sub-picosecond time scale.

Published
2011

23. Ultrafast dynamics in metallic and semiconducting carbon nanotubes

Author

Jared Crochet, Josh Holt, Tobias Hertel, Z. Valy Vardeny, Guglielmo Lanzani, and Larry Lüer

Subjects
Physics, Graphene, Selective chemistry of single-walled nanotubes, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, law.invention, Photoexcitation, Optical properties of carbon nanotubes, Condensed Matter::Materials Science, symbols.namesake, Thermalisation, Dirac fermion, Absorption band, law, Lattice (order), symbols, Atomic physics
Abstract

Transient polarized pump/probe transmission changes upon pulse photoexcitation at 1.6 eV were measured in chiral enriched carbon nanotubes ensembles of both metallic and semiconductor characters, in a very broad probe spectral range from mid-IR to visible, combining several ultrafast laser systems. We identify a photoinduced absorption band at $\ensuremath{\sim}0.7\text{ }\text{eV}$ as due to hot Dirac fermions in the metallic tubes and measure its dynamics. The hot carriers equilibrate within the electronic system in $\ensuremath{\sim}400\text{ }\text{fs}$ and with the lattice within $\ensuremath{\sim}2\text{ }\text{ps}$; in agreement with hot Dirac fermions thermalization in graphene. We also assign excitonic transitions in the semiconducting tubes, mainly of (6,5) chirality; in particular, an intraexciton transition at $\ensuremath{\sim}0.4\text{ }\text{eV}$ represents a lower limit for the exciton binding energy.

Published
2009
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24. High Efficiency Millimeter-Scale Crystalline Perovskite Solar Cells

Author

Aditya Mohite, Wanyi Nie, Hsinhan Tsai, Reza Asadpour, Jean-Christophe Blancon, Amanda Neukirch, Gautam Gupta, Jared Crochet, Manish Chhowalla, Muhammad Alam, Hsing-Lin Wang, and Sergei Tretiak

Abstract

Current state-of-the-art photovoltaics utilize high purity single-crystal semiconductors grown by sophisticated, high temperature crystal-growth processes. Alternative emerging solar cell technologies based on solution-processed materials promise to deliver power at lower cost, but so far have had limited success due to the presence of defects in the bulk and at the grain boundaries. Improving the crystal size and quality of solution-processed films could lead to unprecedented improvements in photovoltaic performance. However, large-scale crystal growth is challenging in solution-based deposition where molecular kinetics are limited by the low processing temperature. Here, for the first time we demonstrate organometallic perovskites thin-films composed of extra-ordinarily large crystalline grains (1-2 mm), fabricated using a new processing technique. The increase in the grain-size directly correlates to a dramatic increase in the efficiency, as a direct consequence of increased charge carrier mobility and reduction in defect densities. Our measured efficiency values approach ~18%, which is among the highest reported. These devices are extremely robust, exhibiting no degradation with voltage sweep direction or the rate at which the voltage was scanned. We anticipate that this technique for growing high quality large-area crystals at low temperature with low defect concentration will be universally applicable to a wide variety of other material systems thus providing a solution to a long-standing scientific challenge of overcoming polydispersity, defects and grain boundary recombination in solution-processed thin-films. From the perspective of the global photovoltaics community, these results are expected to lead the field towards the synthesis of wafer-scale crystalline perovskites necessary for the fabrication of high-efficiency single-junction and hybrid (semiconductor and perovskite) tandem planar cells. In addition, I will also discuss design principles that govern the photostability in these systems.

Published
2015
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25. Temperature distribution in selective laser-tissue interaction

Author

Surya Gnyawali, Evan C. Lemley, Jared Crochet, Wei R. Chen, Yichao Chen, and Lihong V. Wang

Subjects
Materials science, Monte Carlo method, Biomedical Engineering, Models, Biological, law.invention, Biomaterials, Optics, law, Neoplasms, Animals, Humans, Computer Simulation, Irradiation, Laser power scaling, Diagnosis, Computer-Assisted, Diffusion (business), Absorption (electromagnetic radiation), business.industry, Temperature, Hyperthermia, Induced, Photothermal therapy, Laser, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Energy Transfer, Laser Therapy, business, Monte Carlo Method, Thermal energy, Biomedical engineering
Abstract

Selective photothermal interaction using dye enhancement has proven to be effective in minimizing surrounding tissue damage and delivering energy to target tissue. During laser irradiation, the process of photon absorption and thermal energy diffusion in the target tissue and its surrounding tissue are crucial. Such information allows the selection of proper operating parameters such as dye concentrations, laser power, and exposure time for optimal therapeutic effect. Combining the Monte Carlo method for energy absorption and the finite difference method for heat diffusion, the temperature distributions in target tissue and surrounding tissue in dye enhanced laser photothermal interaction are obtained. Different tissue configurations and dye enhancement are used in the simulation, and different incident beam sizes are also used to determine optimum beam sizes for various tissue configurations. Our results show that the algorithm developed in this study could predict the thermal outcome of laser irradiation. Our simulation indicates that with appropriate absorption enhancement of the target tissue, the temperature in the target tissue and in the surrounding tissue can be effectively controlled. This method can be used for optimization of lesion treatment using laser photothermal interactions. It may also provide guidance for laser immunotherapy in cancer treatment, since the immunological responses are believed to be related to tissue temperature changes.

Published
2006

26. Invited Presentation: The Role of Dispersing Molecules on the Separation and Optical Properties of Carbon Nanotubes

Author

Navaneetha K Subbaiyan, Sofie Cambre, A. Nicholas Parra-Vasquez, Erik Haroz, Jared Crochet, Brahim Lounis, Laurent Cognet, Steven Doorn, and Juan G Duque

Subjects
Condensed Matter::Materials Science
Abstract

When studying the optical properties of single-walled carbon nanotubes (SWCNTs), it is known that the dispersing agent(s) play an important role in the observed optical and electronic properties as well as in the separation of tubes. However, fundamental and applied reports are hindered by poor control over the interaction between the dispersant molecules and the nanotubes. Here I will discuss how interfacial chemistry affects the separation of SWCNTs and their optical properties. Compelling spectroscopic evidence has shown that surfactant composition, concentration, and structure are crucial factors to separate SWCNTs and obtain highly stable and fluorescent nanotube dispersions.

Published
2014
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32. Ultrafast excitation energy transfer in small carbon nanotube aggregates

Author

Larry Lüer, Giulio Cerullo, Tobias Hertel, Guglielmo Lanzani, and Jared Crochet

Subjects
education.field_of_study, Materials science, Exciton, Degenerate energy levels, Population, Physics::Optics, Carbon nanotube, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Molecular physics, law.invention, Free induction decay, Condensed Matter::Materials Science, law, Physics::Atomic and Molecular Clusters, Atomic physics, education, Femtochemistry, Ultrashort pulse, Excitation
Abstract

Ultrafast inter-tube exciton transfer in small aggregates of carbon nanotubes is studied by femtosecond spectroscopy with degenerate broadband pulses. After separation of population dynamics from coherent effects, transfer times below 10 fs are obtained.

33. Critical Role of Interface and Crystallinity on the Performance and Photostability of Perovskite Solar Cell on Nickel Oxide

Author

Pulickel M. Ajayan, Jared Crochet, Mikael Kepenekian, Boubacar Traore, Costas C. Stoumpos, Olivier Durand, Wanyi Nie, Mercouri G. Kanatzidis, Jacky Even, Aditya D. Mohite, Jean-Christophe Blancon, Claudine Katan, Hsinhan Tsai, Sergei Tretiak, Fangze Liu, Los Alamos National Laboratory (LANL), Rice University [Houston], Northwestern University [Evanston], Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), 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), Institut des Fonctions Optiques pour les Technologies de l'informatiON (Institut FOTON), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS), 08SPCE973, U.S. Department of Energy, Horizon 2020, ANR-15-CE05-0018,TRANSHYPERO,Vers une compréhension des propriétés de transport électronique des cellules solaires basées sur les pérovskites hybrides(2015), European Project: 687008,H2020,H2020-FETOPEN-2014-2015-RIA,GOTSolar(2016), 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), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-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)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), and Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)

Subjects
Materials science, Perovskite solar cell, 02 engineering and technology, 010402 general chemistry, photostability, 7. Clean energy, 01 natural sciences, perovskite solar cells, Crystallinity, Tetragonal crystal system, [CHIM]Chemical Sciences, General Materials Science, Thin film, crystallinity, Perovskite (structure), LiNiO, [PHYS]Physics [physics], Open-circuit voltage, business.industry, Mechanical Engineering, Nickel oxide, Non-blocking I/O, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Mechanics of Materials, Optoelectronics, 0210 nano-technology, business
Abstract

International audience; Hybrid perovskites are on a trajectory toward realizing the most efficient single-junction, solution-processed photovoltaic devices. However, a critical issue is the limited understanding of the correlation between the degree of crystallinity and the emergent perovskite/hole (or electron) transport layer on device performance and photostability. Here, the controlled growth of hybrid perovskites on nickel oxide (NiO) is shown, resulting in the formation of thin films with enhanced crystallinity with characteristic peak width and splitting reminiscent of the tetragonal phase in single crystals. Photophysical and interface sensitive measurements reveal a reduced trap density at the perovskite/NiO interface in comparison with perovskites grown on poly(3,4-ethylene dioxy thiophene) polystyrene sulfonate. Photovoltaic cells exhibit a high open circuit voltage (1.12 V), indicating a near-ideal energy band alignment. Moreover, photostability of photovoltaic devices up to 10-Suns is observed, which is a direct result of the superior crystallinity of perovskite thin films on NiO. These results elucidate the critical role of the quality of the perovskite/hole transport layer interface in rendering high-performance and photostable optoelectronic devices.

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