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Flexible and lightweight Cu(In,Ga)Se2 (CIGS) thin-film solar cells are promising for versatile applications, but there is limited understanding of stress-induced changes. In this study, the charge carrier generation and trapping behavior under mechanical stress was investigated using flexible CIGS thin-film solar cells with various alkali treatments. Surface current at the CIGS surface decreased by convex bending, which occurs less with the incorporation of alkali metals. The formation energy of the carrier generating defects increased in convex bending environments clarifying the degradation of the surface current. Moreover, alkali-related defects had lower formation energy than the intrinsic acceptors, mitigating current degradation in mechanical stress condition. The altered defect energy levels were attributed to the deformation of the crystal structure under bending states. This study provides insights into the mitigating of strain-induced charge degradation for enhancing the performance and robustness of flexible CIGS photovoltaic devices. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries suffer from reduced capacities and stabilities at low temperature due to poor Li intercalation to the graphite anode. Graphite has a high activation energy (∼0.6 eV) to accommodate Li ions, resulting in a substantial capacity drop at low temperatures. Additionally, it can induce the formation of Li dendrites on the surface of graphite. To address this issue, we designed and synthesized a redox-active fluorothianthrene-based MOF (SKIER-5). SKIER-5, which undergoes three-electron redox reactions resulting from the fluorothianthrene-based organic ligand and Ni, exhibited excellent electrochemical performance at various temperatures when used as an anode. In particular, the discharge capacities of SKIER-5 were significantly higher than those of commercial graphite at low temperatures (<−10 °C) because of the lower activation energy (∼0.23 eV) for charge transfer. Moreover, it maintained stability when cycled at −20 °C, highlighting its potential as a promising anode material in low-temperature environments. [ABSTRACT FROM AUTHOR]

The demand for fast-charging lithium-ion batteries (LIBs) with long cycle life is growing rapidly due to the increasing use of electric vehicles (EVs) and energy storage systems (ESSs). Meeting this demand requires the development of advanced anode materials with improved rate capabilities and cycling stability. Graphite is a widely used anode material for LIBs due to its stable cycling performance and high reversibility. However, the sluggish kinetics and lithium plating on the graphite anode during high-rate charging conditions hinder the development of fast-charging LIBs. In this work, we report on a facile hydrothermal method to achieve three-dimensional (3D) flower-like MoS2 nanosheets grown on the surface of graphite as anode materials with high capacity and high power for LIBs. The composite of artificial graphite decorated with varying amounts of MoS2 nanosheets, denoted as MoS2@AG composites, deliver excellent rate performance and cycling stability. The 20−MoS2@AG composite exhibits high reversible cycle stability (~463 mAh g−1 at 200 mA g−1 after 100 cycles), excellent rate capability, and a stable cycle life at the high current density of 1200 mA g−1 over 300 cycles. We demonstrate that the MoS2-nanosheets-decorated graphite composites synthesized via a simple method have significant potential for the development of fast-charging LIBs with improved rate capabilities and interfacial kinetics. [ABSTRACT FROM AUTHOR]

Correction for 'Redox-active conductive metal–organic framework with high lithium capacities at low temperatures' by Yogendra Kumar et al., J. Mater. Chem. A, 2024, https://doi.org/10.1039/D4TA01779J. [ABSTRACT FROM AUTHOR]

Phase-pure interpenetrated MOF-5 ([Zn4(O)(BDC)3]) was synthesized by pH* control in a reaction medium, and its stability in the presence of epoxides was confirmed by powder X-ray diffraction analysis. Interpenetrated MOF-5/tetra-n-butylammonium bromide (int-MOF-5/n-Bu4NBr) showed a high catalytic activity toward CO2 fixation to epoxide to synthesize cyclic carbonates. The conversions of propylene oxide (PO) and styrene oxide (SO) by int-MOF-5/n-Bu4NBr were almost two times higher than those by MOF-5/n-Bu4NBr under the same conditions. From a kinetics point of view, the coupling reaction rate of PO and CO2 was much higher than that of SO and CO2, which may be due to steric effects. The optimized geometries by the density functional theory calculation revealed that Lewis acidic Zn(II) sites of tetranuclear {Zn4O} clusters can work as the catalytic center to bind epoxides to open the rings by a nucleophilic attack. This co-catalyst system may be useful for the synthesis of cyclic carbonate by CO2 fixation. [ABSTRACT FROM AUTHOR]

α-In 2 Se 3 semiconductor crystals realize artificial synapses by tuning in-plane and out-of-plane ferroelectricity with diverse avenues of electrical and optical pulses. While the electrically induced ferroelectricity of α-In 2 Se 3 shows synaptic memory operation, the optically assisted synaptic plasticity in α-In 2 Se 3 has also been preferred for polarization flipping enhancement. Here, the synaptic memory behavior of α-In 2 Se 3 is demonstrated by applying electrical gate voltages under white light. As a result, the induced internal electric field is identified at a polarization flipped conductance channel in α-In 2 Se 3 /hexagonal boron nitride (hBN) heterostructure ferroelectric field effect transistors (FeFETs) under white light and discuss the contribution of this built-in electric field on synapse characterization. The biased dipoles in α-In 2 Se 3 toward potentiation polarization direction by an enhanced internal built-in electric field under illumination of white light lead to improvement of linearity for long-term depression curves with proper electric spikes. Consequently, upon applying appropriate electric spikes to α-In 2 Se 3 /hBN FeFETs with illuminating white light, the recognition accuracy values significantly through the artificial learning simulation is elevated for discriminating hand-written digit number images., (© 2024 Wiley‐VCH GmbH.)

Isostructural [M 2 (DOBDC)(EG) 2 ] (M = Mg, Co, Ni) frameworks are first synthesized by controlling the pH* in the reaction medium. Coordinated ethylene glycols form a hexagonal OH cluster, which works as a template to grow single crystals with high crystallinity. After the liberation of solvated molecules, [M 2 (DOBDC)] shows notably higher surface areas than the reported values and completely different CO 2 and CO separation properties depending on the kinds of unsaturated metal. Therefore, breakthrough experiments using a CO 2 /CO mixed gas show that Mg-MOF has a longer breakthrough time for CO 2 than for CO, whereas Co/Ni-MOFs have longer breakthrough times for CO than for CO 2 . Apart from CO 2 and CO, other gases such as CH 4 , H 2 , and N 2 were almost not adsorbed at all in these materials at 298 K. To reveal the role of unsaturated metal sites, CO 2 and CO adsorption sites are unequivocally determined by single-crystal X-ray diffraction analysis. One of very interesting discoveries is that there are two CO 2 and CO adsorption positions (sites A and B) in the hexagonal channels. Site A is the unsaturated metal center working as Lewis acidic sites, and site B is the secondary adsorption site located between two A sites. A close inspection of crystal structures reveals that unsaturated Co(II) and Ni(II) sites adsorb both CO 2 and CO, whereas the unsaturated Mg(II) sites strongly capture only CO 2 , not CO. Density functional theory calculations elucidate the discrepancy in CO affinity: Co(II) and Ni(II) form strong π-back-donating bonds with CO via electron transfer from the d orbitals of the transition metals to the antibonding molecular orbitals of CO, whereas Mg(II) does not participate in electron transfer or orbital overlap with CO. This observation provides new insight into the synthesis of novel functional materials with high CO 2 /CO separation performance.

Several oxide materials have attracted much interest for the application in spintronic devices due to unusual properties originating from the strongly correlated orbital and spin degrees of freedom. One missing part in oxide spintronics is a good spin channel featured by strong spin-orbit coupling (SOC) which enables an efficient control of the electron's spin. We have systematically investigated the dependence of the SOC strength of Sr(Nb x Ti 1-x )O 3 thin films on Nb concentration (n Nb  = 2~20 at. %) as a deeper exploration of a recent finding of the strong SOC in a heavily Nb-doped SrTiO 3 (Sr(Nb 0.2 Ti 0.8 )O 3 ) epitaxial film. Apart from a finding of a proportionality of the SOC to n Nb , we have observed an intriguing temperature dependence of the SOC strength and the anisotropic magnetoresistance (MR) in the intermediate n Nb region. These phenomena are associated with the temperature dependence of Landé g-factor and the change of the band structure, which is consistent with the result of density functional theory (DFT) calculation.