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Lithium nickel oxide (LNO) is an attractive positive electrode active material for lithium ion batteries (LIBs) due to its high reversible specific capacity and absence of cobalt. Nevertheless, it is prone to structural instabilities that lead to rapid capacity fading, safety concerns and shows in average a lower voltage than mixtures with cobalt, limiting its applicability to date. Herein this study introduces the sulfur‐based electrolyte additive, benzo[d][1,3,2]dioxathiole 2,2‐dioxide (DTDPh), to stabilize the LNO electrode and study its effects on interphase compositions by means of complementary electrochemical and spectroscopic techniques. Obtained results demonstrate an improved galvanostatic cycling performance in terms of cycle life and achievable specific discharge capacity that significantly outperform the common film‐forming additive vinylene carbonate (VC). The cycle life is increased from 102 to 147 cycles compared to the baseline electrolyte and the accumulated discharge energy until end of life is increased by 45%. This study furthermore provides strong evidence of a significant cross‐talk and negative interplay between DTDPh and VC when both are present in the electrolyte formulation. Mechanistic consideration based on density functional theory (DFT) calculations suggest the formation of mobile poly(VC) species, which is supported by the results of post mortem analysis of the resulting interphases. [ABSTRACT FROM AUTHOR]

The timely arrival of novel materials plays a key role in bringing advances to society, as the pace at which major technological breakthroughs take place is usually dictated by the discovery rate at which novel materials are identified within chemical space. High‐throughput experimentation and computation strategy, now widely considered as a watershed in accelerating the discovery and optimization of novel materials in virtually every field, enables simultaneous screening, synthesis and characterization of large arrays of different material classes toward identification of the lead candidates for given system and targeted application. However, the ability to acquire data, through the continued advancement of automation platforms and workflows especially in the field of battery research and development, often outpaces the ability to optimally leverage obtained data for improved decision‐making. Closing this gap inevitably calls for adapted algorithms, development of reliable predictive models and enhanced integration with machine learning, deep learning, and artificial intelligence. This Review aims to highlight state‐of‐the‐art achievements along with an assessment of current and future challenges as well as resulting perspectives toward accelerated development of advanced battery electrolytes and their interfaces. [ABSTRACT FROM AUTHOR]

We have investigated the core levels and the valence band of (Ge2Sb2Te5)1-x(In3Sb1Te2)x quaternary phase system (IGST) by means of x-ray photoelectron spectroscopy. A systematic shift of Sb 3d and Ge 2p core-level peaks toward lower binding energies side was observed with increasing indium amount, whereas the In 3d and Te 3d core peaks showed less change. The Sb 3d and Ge 2p core-level shift is attributed to an increase in the electronic charge of p-electrons dependent of indium amount. The valence band spectra show a distinct change in the sp configuration with indium concentration change. The change in the local bonding as the indium amount increase has a profound impact on both local atomic arrangement and amorphous-to-crystalline transformation temperature. The difference in the photoemission spectra have been discussed according to a simple structural model suggesting that the Na site in IGST can be occupied by Te, Sb, In, and vacancy, whereas in GST it is occupied only by Te. [ABSTRACT FROM AUTHOR]

Addressing the oxidation state of functional materials such as transition metal oxides is a current critical challenge and requires new methodologies to characterize their electronic structure within surface to bulk resolution at the nanometer scale. One approach to this issue is the combination of co‐localized soft and hard X‐ray photoelectron spectroscopies for a non‐destructive depth profiling. In this work, we demonstrate the capability to characterize the oxidation state of cobalt in LiCoO2 thin films, a model electrode material in the Li‐ion battery field, within the first 15 nm. The capability of the methodology to address the surface evolution of the cobalt oxidation state is tested through a proof of concept surface modification introduced by Ar‐ion sputtering. To address the cobalt local electronic structure at different depths from the extreme surface, we exploited Auger‐free Hard X‐ray photoelectron spectroscopy (HAXPES) spectra to fit the Co 2p core‐level features in the X‐ray photoelectron spectroscopy (XPS) spectra. This approach may pave the way for a better understanding of the surface electronic structure changes in transition metal oxides driven by their applications in a broad range of technologies. [ABSTRACT FROM AUTHOR]

Abstract: We have investigated the effect of Au-ion treatment on the work function and the electronic structure change of reduced graphite oxides (RGOs). Au-ions were reduced spontaneously by extracting electrons (i) from sp2 carbons of RGO at low concentration and (ii) from some oxygen-related functional groups at high concentration. This implies that the work function was modulated by the amount of charges transferred to Au-ions. The sheet resistance of the RGO film was improved with Au-ion treatment. This was explained in terms of electron donation to Au-ions that eventually led to a p-type doping in RGO film. [Copyright &y& Elsevier]

We investigated the effects of X‐ray beam damage during X‐ray photoelectron spectroscopy measurement on LiNiO2 electrodes. The degree of damage induced by lab‐based and synchrotron X‐ray radiation has been compared between pristine and cycled electrodes, highlighting the role of positive solid electrode–electrolyte interphase to protect the cycled LiNiO2 surface from beam damage. The possible steps to avoid or at least reduce the beam‐induced effects are outlined. [ABSTRACT FROM AUTHOR]

Driven by the continuous search for improving performances, understanding the phenomena at the electrode/electrolyte interfaces has become an overriding factor for the success of sustainable and efficient battery technologies for mobile and stationary applications. Toward this goal, rapid advances have been made regarding simulations/modeling techniques and characterization approaches, including high‐throughput electrochemical measurements coupled with spectroscopies. Focusing on Li‐ion batteries, current developments are analyzed in the field as well as future challenges in order to gain a full description of interfacial processes across multiple length/timescales; from charge transfer to migration/diffusion properties and interphases formation, up to and including their stability over the entire battery lifetime. For such complex and interrelated phenomena, developing a unified workflow intimately combining the ensemble of these techniques will be critical to unlocking their full investigative potential. For this paradigm shift in battery design to become reality, it necessitates the implementation of research standards and protocols, underlining the importance of a concerted approach across the community. With this in mind, major collaborative initiatives gathering complementary strengths and skills will be fundamental if societal and environmental imperatives in this domain are to be met. [ABSTRACT FROM AUTHOR]

Short channel device performance of deep-submicron gate length oxide thin film transistor (TFT) with amorphous InGaZnO (a-IGZO) active semiconductor is presented. Remarkable electrical properties of short channel oxide TFT were achieved utilizing crucial structure and material optimization such as self aligned gate structure with homo junction, multi-channel with rounded corners, and high-κ gate dielectric. It was found that various device performance parameters of short channel-oxide TFTs were significantly influenced by materials, processes, and structural geometry, which should be more carefully designed. [ABSTRACT FROM AUTHOR]

A VOx-impregnated oxide cathode for lithium ion batteries exhibits a substantial drop in oxygen evolution during high voltage operation. An electrolyte was found to catalyze the gas evolution, and the VOxlayer could protect the cathode oxide surface from the electrolyte and stabilize the surface oxide ions during their electrochemical oxidation. [ABSTRACT FROM AUTHOR]

Graphene hydrogels with high electrical conductivity were prepared by a one-step process using hydrazine hydrate as gel assembly agent (GH-HD). Conventional two-step process of gel formation and further reduction to prepare highly conducting gels was replaced by a single step involving equivalent amount of hydrazine. Optimized graphene oxide concentration was established to facilitate such monolith formation. Extensive characterization and control studies enabled understanding of the material properties and gel formation mechanism. The synthesized gel shows a high electrical conductivity of 1141 S/m. The supercapacitor based on GH-HD delivers a high specific capacitance of 190 F/g at a current density of 0.5 A/g and 123 F/g at very high current density of 100 A/g. Furthermore, excellent power capability and cyclic stability were also observed. 3D macroporous morphology of GH-HD makes it ideal for high rate supercapacitor applications. [ABSTRACT FROM AUTHOR]

Using Si as anode materials for Li-ion batteries remain challenging due to its morphological evolution and SEI modification upon cycling. The present work aims at developing a composite consisting of carbon-coated Si nanoparticles (Si@C NPs) intimately embedded in a three-dimensional (3D) graphene hydrogel (GHG) architecture to stabilize Si inside LiB electrodes. Instead of simply mixing both components, the novelty of the synthesis procedure lies in the in situ hydrothermal process, which was shown to successfully yield graphene oxide reduction, 3D graphene assembly production, and homogeneous distribution of Si@C NPs in the GHG matrix. Electrochemical characterizations in half-cells, on electrodes not containing additional conductive additive, revealed the importance of the protective C shell to achieve high specific capacity (up to 2200 mAh.g−1), along with good stability (200 cycles with an average Ceff > 99%). These performances are far superior to that of electrodes made with non-C-coated Si NPs or prepared by mixing both components. These observations highlight the synergetic effects of C shell on Si NPs, and of the single-step in situ preparation that enables the yield of a Si@C-GHG hybrid composite with physicochemical, structural, and morphological properties promoting sample conductivity and Li-ion diffusion pathways. [ABSTRACT FROM AUTHOR]

Copper/copper oxide (Cu/Cu2O) electrodes are known to display interesting electrocatalytic performances for the reduction of CO2, and thus, deserve further investigation for optimization. Here, we show that the addition of nitrogen- based organic additives greatly improves the activity of these electrodes (higher current densities, greater selectivity, and higher faradaic yields). The best effector is found to be tetramethyl cyclam. For example, electrolysis at -2.0 V versus Fc+/Fc in CO2-saturated DMF/H2O (99:1, v/v) in the presence of this effector results in formic acid with almost 90% faradaic yield. SEM and XPS analysis of the electrode surface reveals that the organic additive promotes the formation of active Cu0 nanoparticles from Cu2O during electrolysis. This simple approach provides a straightforward strategy toward the optimization of Cu/Cu2O electrodes. [ABSTRACT FROM AUTHOR]

To achieve high-mobility and high-reliability oxide thin film transistors (TFTs), ZnON has been investigated following an anion control strategy based on the substitution of oxygen with nitrogen in ZnO. However, as nitrogen possesses, compared to oxygen, a low reactivity with Zn, the chemical composition of ZnON changes easily, causing in turn a degradation of both the performance and the stability. Here, we have solved the issues of long-time stability and composition nonuniformity while maintaining a high channel mobility by adopting the argon plasma process, which can delay the reaction of oxygen with Zn-O-N; as a result, owing to the formation of very fine nano-crystalline structure in stable glassy phase without changes in the chemical composition, the material properties and stability under e-radiation have significantly improved. In particular, the channel mobility of the ZnON TFTs extracted from the pulsed IV method was measured to be 138 cm²/V s. [ABSTRACT FROM AUTHOR]

The present work aims to better understand the effect of operating temperature on the degradation of Solid Oxide Electrolysis Cells (SOECs). The studied SOECs consist of La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ -Ce 0.8 Gd 0.2 O 2-δ (LSCF-GDC) oxygen electrode, GDC diffusion barrier layer, Y 0.16 Zr 0.84 O 1.92 (YSZ) electrolyte and Ni-YSZ hydrogen electrode. Durability tests are carried out at 750, 800 and 850 °C for 2000 h at −1 A cm−2, using 10/90 vol% H 2 /H 2 O and dry air at the hydrogen and oxygen electrodes, respectively. The electrochemical impedance spectra measured before and after ageing reveal a strong evolution related to the hydrogen electrode, while the change in the oxygen electrode contribution remains negligible. A set of advanced characterization techniques are employed to study the cell degradation. For the hydrogen electrode, a large Ni depletion is observed after ageing, which increases with the operating temperature. The analysis of the oxygen electrode shows an elemental inter-diffusion between the LSCF-GDC/GDC/YSZ layers on the manufactured cells that seems to not evolve significantly upon operation. Moreover, the presence of SrZrO 3 is not detected in the pristine cell and in the operated ones. Besides, only a limited LSCF decomposition is found in good agreement with the electrochemical characterizations. Hypotheses that could explain the good oxygen electrode stability are discussed. • Effect of temperature on solid oxide electrolysis cells degradation. • Higher Ni depletion at 850 °C than 750 °C. • Role of the interdiffusion layer on the cell durability. • Intermixing between LSCF and GDC with diffusion of Ce and Gd into LSCF. • Limited Sr segregation after operation under electrolysis current. [ABSTRACT FROM AUTHOR]

Lithium-rich disordered rocksalt Li2TiS3 offers large discharge capacities (>350 mAh·g−1) and can be considered a promising cathode material for high-energy lithium-ion battery applications. However, the quick fading of the specific capacity results in a poor cycle life of the system, especially when liquid electrolyte-based batteries are used. Our efforts to solve the cycling stability problem resulted in the discovery of new high-energy selenium-substituted materials (Li2TiSexS3−x), which were prepared using a wet mechanochemistry process. X-ray diffraction analysis confirmed that all compositions were obtained in cation-disordered rocksalt phase and that the lattice parameters were expanded by selenium substitution. Substituted materials delivered large reversible capacities, with smaller average potentials, and their cycling stability was superior compared to Li2TiS3 upon cycling at a rate of C/10 between 3.0–1.6 V vs. Li+/Li. [ABSTRACT FROM AUTHOR]

A novel well-defined precatalyst for ammonia-selective catalytic reduction of NOx (NH3-SCR), namely, [W(≡CtBu)(CH2tBu)3]/CeO2, was prepared by surface organometallic chemistry and then characterized. Due to the high dispersion of the active phase, this catalyst showed excellent activity after calcination at 500 °C, described by up to 99% conversion of NOx, high N2 selectivity, broad operation temperature window (225–500 °C), and extremely high durability for the selective catalytic reduction of NOx with NH3. [ABSTRACT FROM AUTHOR]

We introduce single-phase In–Ge–Sb–Te (IGST) quaternary thin film (fcc structure when crystallized) deposited by cosputtering from Ge2Sb2Te5(GST) and In3Sb1Te2 targets. This film, compared with the GST ternary system, provides a significant increase of amorphous-to-crystalline transformation temperature. High-resolution x-ray photoelectron spectroscopy (HRXPS) revealed that, with increasing In amounts, the Sb 4d and Ge 3d core peaks shift toward lower binding energies (BEs), with negligible changes in spectral linewidths, whereas the In 4d and Te 4d core peaks show insignificant changes in BEs. HRXPS interpretation suggests that the Na site in IGST can be occupied by Te, Sb, In, and vacancy, whereas in GST it is occupied only by Te. [ABSTRACT FROM AUTHOR]

• The air stability of polymer layers p-doped with molybdenum dithiolene complexes is investigated. • Unstable doping signatures are observed under ambient air, related to a dedoping process. • Oxidation and degradation of the dopant molecule are evidenced by XPS analysis. Doping efficiency and stability are crucial requirements for the integration of doped organic semiconductors in optoelectronic devices. This work presents a detailed experimental study on the air stability of p-doped systems based on a low-bandgap polymer, poly[(4,8-bis-(2-ethylhexyloxy)-benzo(1,2-b:4,5-b')dithiophene)-2,6-diyl-alt-(4-(2-ethylhexanoyl)-thieno[3,4-b]thiophene-)-2-6-diyl) (PBDTTT-c) doped with a strong molecular p-dopant, i.e. molybdenum tris[1-(trifluoroethanoyl)-2-(trifluoromethyl) ethane-1,2-dithiolene] (Mo(tfd-COCF 3) 3). The electrical conductivity and the optical absorption are measured for different dopant concentrations in argon atmosphere, and their variations monitored as a function of the air exposure time. The results indicate a clear instability under ambient air related to a dedoping process, which is particularly pronounced in ultra-thin (< 50 nm) doped layers. By evaluating the stability of the p-doped polymer layers under different atmospheres (ambient air, anhydrous air and argon), the detrimental impact of moisture and/or O 2 (H 2 0) n complexes is highlighted. X-ray Photoelectron Spectroscopy (XPS) revealed that the p-doping instability in ambient air can be assigned to changes in the oxidation state of the metallic center as well as to an intrinsic degradation of the dopant molecule. This study unravels an important degradation mechanism with this class of dopants that should be taken under consideration and solved for future integration of ultrathin p-doped layers in printed electronic devices. [ABSTRACT FROM AUTHOR]

The present paper reports the energy loss near-edge structure (ELNES) study of monoclinic HfO2 (m-HfO2) and tantalum doped m-HfO2 (Ta0.1Hf0.9O2) thin films prepared by radio frequency magnetron co-sputtering method. A change in the O K-ELNES spectra was observed as the amount of dopant increases. In order to precise the common features and the differences as a function of Ta defect nature (substitutional or interstitial) in HfO2, the O K-ELNES were commented with respect to density functional theory calculations implemented in Vienna ab initio simulation package code. The calculated Ta doped HfO2 band structure showed that substitutional tantalum is the dominant defect and the spectral differences between doped and non-doped HfO2 are mainly originated from the change in the local cation distribution around the oxygen atoms. [ABSTRACT FROM AUTHOR]

The linear, two-coordinate and isostructural heteroleptic [M(IPr){N(SiMe3)2}] (IPr = 1,3-bis(diisopropylphenyl)-imidazol-2-ylidene), formally MI complexes (M = Co, 3; Fe, 4) were obtained by the reduction of [M(IPr)Cl{N(SiMe3)2}] with KC8, or [Co(IPr){N(SiMe3)2}2] with mes*PH2, mes* = 2,4,6-tBu3C6H2. The magnetism of 3 and 4 implies CoII and FeII centres coupled to one ligand-delocalized electron, in line with XPS and XANES data; the ac susceptibility of 4 detected a pronounced frequency dependence due to slow magnetization relaxation. Reduction of [Fe(IPr)Cl{N(SiMe3)2}] with excess KC8 in toluene gave the heteronuclear ‘inverse-sandwich’ Fe–K complex 7, featuring η6-toluene sandwiched between one Fe0 and one K+ centre. [ABSTRACT FROM AUTHOR]

Poly(3,4-ethylenedioxythiophene) (PEDOT) is certainly the most known and most used conductive polymer because it is commercially available and shows great potential for organic electronic, photovoltaic, and thermoelectric applications. Studies dedicated to PEDOT films have led to high conductivity enhancements. However, an exhaustive understanding of the mechanisms governing such enhancement is still lacking, hindered by the semicrystalline nature of the material itself. In this article, we report the development of highly conductive PEDOT films by controlling the crystallization of the PEDOT chains and by a subsequent dopant engineering approach using iron(III) trifluoromethanesulfonate as oxidant, N-methyl pyrrolidone as polymerization rate controller and sulfuric acid as dopant. XRD, HRTEM, Synchrotron GIWAXS analyses and conductivity measurements down to 3 K allowed us to unravel the organization, doping, and transport mechanism of these highly conductive PEDOT materials. N-methyl pyrrolidone promotes bigger crystallites and structure enhancement during polymerization, whereas sulfuric acid treatment allows the replacement of triflate anions by hydrogenosulfate and increases the charge carrier concentration. We finally propose a charge transport model that fully corroborates our experimental observations. These polymers exhibit conductivities up to 5400 S cm-1 and thus show great promise for room temperature thermoelectric applications or ITO alternative for transparent electrodes. [ABSTRACT FROM AUTHOR]

The interfacing of polyoxometalates and graphene can be considered to be an innovative way to generate hybrid structures that take advantage of the properties of both components. Polyoxometalates are redox-sensitive and photosensitive compounds with high temperature stability (up to 400 °C for some), showing tunable properties depending on the metal incorporated inside the complex. Graphene has a unique electronic band structure combined with good material properties for electrical and optical applications. The spontaneous, rather than electrochemical, functionalization of epitaxial graphene on SiC with Keggin phosphomolybdate derivative TBA3[PMo11O39{Sn(C6H4)CC(C6H4)N2}] (named KMoSn[N2+]) bearing a phenyl diazonium unit is investigated. Graphene decoration is evidenced by means of AFM, Raman, XPS, and cyclic voltammetry, indicating a successful immobilization of the polyoxomolybdate. The covalent bonding of the polyoxometalate to the graphene substrate can be deduced from the appearance of a D band in the Raman spectra and from the loss of mobility in the electrical conduction. High-resolution XPS spectra reveal an electron transfer from the graphene to the Mo complex. The comparison of charge-carrier density measurements before and after grafting supports the p-type doping effect, which is further evidenced by work function UPS measurements. [ABSTRACT FROM AUTHOR]

We report the results of a VAMAS (Versailles Project on Advanced Materials and Standards) interlaboratory study on the measurement of composition in organic depth profiling. Layered samples with known binary compositions of Irganox 1010 and either Irganox 1098 or Fmoc-pentafluoro-l-phenylalanine in each layer were manufactured in a single batch and distributed to more than 20 participating laboratories. The samples were analyzed using argon cluster ion sputtering and either X-ray photoelectron spectroscopy (XPS) or time-of-flight secondary ion mass spectrometry (ToF-SIMS) to generate depth profiles. Participants were asked to estimate the volume fractions in two of the layers and were provided with the compositions of all other layers. Participants using XPS provided volume fractions within 0.03 of the nominal values. Participants using ToF-SIMS either made no attempt, or used various methods that gave results ranging in error from 0.02 to over 0.10 in volume fraction, the latter representing a 50% relative error for a nominal volume fraction of 0.2. Error was predominantly caused by inadequacy in the ability to compensate for primary ion intensity variations and the matrix effect in SIMS. Matrix effects in these materials appear to be more pronounced as the number of atoms in both the primary analytical ion and the secondary ion increase. Using the participants' data we show that organic SIMS matrix effects can be measured and are remarkably consistent between instruments. We provide recommendations for identifying and compensating for matrix effects. Finally, we demonstrate, using a simple normalization method, that virtually all ToF-SIMS participants could have obtained estimates of volume fraction that were at least as accurate and consistent as XPS. [ABSTRACT FROM AUTHOR]

Controlling the stoichiometry of supported bimetallic nanoparticles is essential in many catalytic reactions, notably selective CO 2 hydrogenation. Thus, a new strategy to ensure the preferred stoichiometry (1:1) of supported bimetallic PdZn nanoparticles is presented, involving the deposition of a heterobimetallic precursor, [PdZn(μ-OOCMe) 4 ] 2 on a CeZrO x support. After calcination and reduction, the material contained mainly a PdZn alloy, as revealed by powder XRD and XAFS, and further supported by XPS, TEM-EDX, elemental analysis and in-situ IR at low temperature using CO as probe molecule. Moreover, a minor phase of oxidized Zn was determined by XAFS. This PdZn/CeZrOx reduced catalyst was combined with SAPO-34 to form a tandem catalytic system for CO 2 conversion to hydrocarbons. This system could readily convert CO 2 and H 2 at high temperature (380 °C) into hydrocarbons with a conversion of 24% and high relative selectivity in light hydrocarbons (C2–C3: 82%) with virtually no deactivation of the catalyst after 16 h on stream. Controlled experiments were performed with Pd/CeZrOx and Zn/CeZrOx in order to gain supplementary insights on this system: Pd/CeZrOx gave only methane and Zn/CeZrOx gave mainly CO under the same conditions. The latter clearly shows that the control of the formation of PdZn phase has great impact for the selective production of hydrocarbons. [Display omitted] • Development of PdZn supported on CeO 2 , ZrO 2 and CeZrOx for the conversion of CO 2 to methanol. • Catalyst PdZn/CeZrOx presents highly dispersed bimetallic PdZn nanoparticles with 1:1 ratio. • CO 2 conversion to light hydrocarbons is studied over tandem catalysts comprising PdZn supported on oxide and SAPO-34. • PdZn/CeZrOx/SAPO-34 catalysts present high CO 2 conversion and selectivity in light hydrocabons. [ABSTRACT FROM AUTHOR]

Poly(3,4-ethylenedioxythiophene) (PEDOT) is a transparent conductive polymer widely used in flexible photonic and optoelectronic devices because of its excellent electrical and optical properties. However, its current range of applications is limited by its poor stability under high humidity and solar radiations. Encapsulation is an attractive solution to this problem and the development of a low-temperature and scalable deposition method is highly desirable. In this study, we report the use of spatial atomic layer deposition (SALD) to deposit ultrathin layers of ZnO, TiO 2 , and Al 2 O 3. These nanolayers maintain the electrical performance of the conductive polymer and its high optical transmittance. The use of SALD ensures low-cost and flexible processing with pinhole-free high-quality coatings at atmospheric pressure and high-throughput. The present study is the first to investigate the effect of various multilayer metal oxide encapsulations on the long-term stability of PEDOT-based transparent conductive materials under solar radiations. We demonstrate finally that bilayer TiO 2 /Al 2 O 3 and TiO 2 /ZnO coatings preserve the optoelectronic properties of three different PEDOT-based films, namely PEDOT:OTf (OTf = triflate), PEDOT:Sulf (Sulf = sulfate)and PEDOT:PSS (PSS = PolyStyreneSulfonate) films. [Display omitted] • PEDOT materials are encapsulated using spatial atomic layer deposition. • Deposition of nanolayers is an efficient method to preserve the electrical performances of highly conductive PEDOT. • Bilayer structures TiO 2 /ZnO and TiO 2 /Al 2 O 3 lead to the most effective protection. [ABSTRACT FROM AUTHOR]

Abstract: We report on the fabrication of completely uniform monolayer graphene on a metal thin film over a 150mm Si substrate at a low temperature of 600°C by inductively coupled plasma-enhanced chemical vapor deposition (ICPCVD). Through novel use of bimetallic catalyst such as CuNi and AuNi alloys we were able to control catalytic reaction at the metal surface and grow complete monolayer graphene with a Ni content less than 20at.%. We also found that the 2D/G intensity ratio in the Raman spectra was almost invariant with growth time and the C 1s peak in the XPS spectra was observed only at the metal surface. This implies that monolayer graphene was possibly grown on these Ni-doped copper and gold catalysts by a self-limiting surface reaction under our CVD condition. From DFT calculations, it was shown that the catalytic activity of normally inactive Cu and Au could be enhanced through the addition of Ni atoms at surface sites, providing graphene growth at lower temperatures than pure Cu or Au. The carrier mobility of graphene films grown on these CuNi and AuNi alloy catalyst was measured to be over 9000cm2 V−1 s−1 at room temperature, which is comparable to that of CVD graphene film grown on Cu foil. Therefore, we suggest an efficient way in growing a complete monolayer graphene on thin films at low temperatures, which could be a key issue in the application of graphene devices. [Copyright &y& Elsevier]

Nitrogen in a thin HfO2−xNx layer was observed in the form of dinitrogen molecules by atom probe microscope measurements. To evaluate the chemical state, an ab initio calculation based on monoclinic HfO2 was performed with using oxygen vacancy models combined with interstitial or substitutional nitrogen. The formation of a hafnium dinitrogen complex near the oxygen vacancy was found to considerably lower the system energy. This result contrasts the substitutional nitrogen complex passivating the oxygen vacancy level in the cubic structure and suggests that the structural stability enhanced by the oxygen vacancy-dinitrogen complex restrains the formation of grain boundaries in amorphous HfO2, which are responsible for the large leakage current. [ABSTRACT FROM AUTHOR]

We report the transformation of electronic structures of sp2 graphene to sp3 graphene by UV-light-assisted oxidation. Two distinctive oxidation mechanisms were observed during this metal-insulator transition: (i) At low-oxidation regime, p-doping behavior by oxygen species extracting electrons from graphene and (ii) at high-oxidation regime, n-doping behavior by electron-hopping via strongly localized oxide states. We also found that the dominant oxygen-related functional group by UV-light-assisted oxidation was an epoxide group rather than hydroxyl group, which differed from conventional graphite oxide. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the modulation of optical properties of single-walled carbon nanotubes (SWCNTs) by AuCI3 doping. The van Hove singularity transitions (E11S, E22S, E11M) in absorption spectroscopy disappeared gradually with an increasing doping concentration and a new peak appeared at a high doping concentration. The work function was downshifted up to 0.42 eV by a strong charge transfer from the SWCNTs to AuCl3 by a high level of p-doping. We propose that this large work function shift forces the Fermi level of the SWCNTs to be located deep in the valence band, i.e., highly degenerate, creating empty van Hove singularity states, and hence the work function shift invokes a new asymmetric transition in the absorption spectroscopy from a deeper level to newly generated empty states. [ABSTRACT FROM AUTHOR]

Various electron-donating and -withdrawing groups in aromatic and aliphatic backbones of solvent have been introduced to tailor the electronic structures of single-walled carbon nanotubes (SWCNTs). In the case of solvent with a withdrawing group, electrons were extracted mainly from metallic SWCNTs, whereas small charge transfer was also observed in semiconducting SWCNTs. On the other hand, in the case of solvent with a donating group, electrons were donated to both metallic and semiconducting SWCNTs. This effect was less prominent in solvent with an aliphatic backbone than that with an aromatic backbone. The strong correlation between the sheet resistance and electronic structures of nanotubes is further discussed in conjunction with a modulation of Schottky barrier height. [ABSTRACT FROM AUTHOR]

We have evaluated as-grown MoS2 crystals, epitaxially grown on a monocrystalline sapphire by chemical vapor deposition (CVD), with direct electronic band-structure measurements by energy-filtered k-space photoelectron emission microscopy performed with a conventional laboratory vacuum ultraviolet He I light source under off-normal illumination. The valence states of the epitaxial MoS2 were mapped in momentum space down to 7 eV below the Fermi level. Despite the high nucleation density within the imaged area, the CVD MoS2 possesses an electronic structure similar to the free-standing monolayer MoS2 single crystal, and it exhibits hole effective masses of 2.41±0.05m0, and 0.81±0.05m0, respectively, at Γ and K high-symmetry points that are consistent with the van der Waals epitaxial growth mechanism. This demonstrates the excellent ability of the MoS2 CVD on sapphire to yield a highly aligned growth of well-stitched grains through epitaxial registry with a strongly preferred crystallographic orientation. [ABSTRACT FROM AUTHOR]