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Mixed lead‐tin (Pb:Sn) halide perovskites are promising absorbers with narrow‐bandgaps (1.25–1.4 eV) suitable for high‐efficiency all‐perovskite tandem solar cells. However, solution processing of optimally thick Pb:Sn perovskite films is notoriously difficult in comparison with their neat‐Pb counterparts. This is partly due to the rapid crystallization of Sn‐based perovskites, resulting in films that have a high degree of roughness. Rougher films are harder to coat conformally with subsequent layers using solution‐based processing techniques leading to contact between the absorber and the top metal electrode in completed devices, resulting in a loss of VOC, fill factor, efficiency, and stability. Herein, this study employs a non‐continuous layer of alumina nanoparticles distributed on the surface of rough Pb:Sn perovskite films. Using this approach, the conformality of the subsequent electron‐transport layer, which is only tens of nanometres in thickness is improved. The overall maximum‐power‐point‐tracked efficiency improves by 65% and the steady‐state VOC improves by 28%. Application of the alumina nanoparticles as an interfacial buffer layer also results in highly reproducible Pb:Sn solar cell devices while simultaneously improving device stability at 65 °C under full spectrum simulated solar irradiance. Aged devices show a six‐fold improvement in stability over pristine Pb:Sn devices, increasing their lifetime to 120 h. [ABSTRACT FROM AUTHOR]

The theoretical aspects of the physics of electronic transport in nMOSFETs at the 10-nm scale, long-range Coulomb interactions that might degrade performance and even prevent ballistic transport from occurring are discussed.

In this study, we conduct a comprehensive investigation of the effect of grain, grain boundary and interfacial resistance on the total Li-ion conductivity in Li2OHCl1−xBrx antiperovskite solid electrolytes. We highlight how the thermal expansion coefficient can serve as an indicator for the presence of structural defects, which are difficult to probe directly with X-ray techniques, and their effect on bulk Li-ion conduction. The detrimental effect of grain boundaries on ionic conductivity is investigated by atomistic calculations and validated experimentally by electrochemical impedance spectroscopy on pellets with controlled grain size. The effect of composition on interfacial resistance is probed by electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy. These insights provide design principles to improve Li-ion conductivity in lithium hydroxide halide antiperovskites. [ABSTRACT FROM AUTHOR]

We present a method to treat scattering of electrons with atomic roughness at interfaces, surfaces, and edges on nanometer-scale structures based on local empirical pseudopotentials. This approach merges the computational advantages of macroscopic models based on the shift of a phenomenological 'barrier potential,' with the physical accuracy of models based on modifications of the atomic configuration at the interface/surface/edge. We illustrate the method by considering the dependence of the scattering matrix element on the confinement (inversion) field in free-standing H-terminated Si inversion layers, on the thickness in similarly H-terminated thin-Si bodies, on the diameter of free-standing [100] cylindrical Si nanowires, and on the width of armchair-edge graphene nanoribbons. For these latter structures, we find extremely large scattering rates, whose magnitude - ultimately due to the chirality dependence of the bandgap - renders perturbation theory invalid and prevents us from drawing quantitative conclusions about transport properties. Yet, they show clearly the dominant role played by line-edge roughness in controlling electronic transport in these structures, in agreement with suggestions that transport in narrow and rough ribbons does not occur via extended Bloch states. [ABSTRACT FROM AUTHOR]

Solid-state batteries (SSBs) have received attention as a next-generation energy storage technology due to their potential to superior deliver energy density and safety compared to commercial Li-ion batteries. One of the main challenges limiting their practical implementation is the rapid capacity decay caused by the loss of contact between the cathode active material and the solid electrolyte upon cycling. Here, we use the promising high-voltage, low-cost LiNi 0.5 Mn 1.5 O 4 (LNMO) as a model system to demonstrate the importance of the cathode microstructure in SSBs. We design Al 2 O 3 -coated LNMO particles with a hollow microstructure aimed at suppressing electrolyte decomposition, minimizing volume change during cycling, and shortening the Li diffusion pathway to achieve maximum cathode utilization. When cycled with a Li 6 PS 5 Cl solid electrolyte, we demonstrate a capacity retention above 70% after 100 cycles, with an active material loading of 27 mg cm -2 (2.2 mAh cm -2 ) at a current density of 0.8 mA cm -2 .

To match the high capacity of metallic anodes, all-solid-state batteries require high energy density, long-lasting composite cathodes such as Ni-Mn-Co (NMC)-based lithium oxides mixed with a solid-state electrolyte (SSE). However in practice, cathode capacity typically fades due to NMC cracking and increasing NMC/SSE interface debonding because of NMC pulverization, which is only partially mitigated by the application of a high cell pressure during cycling. Using smart processing protocols, we report a single-crystal particulate LiNi 0.83 Mn 0.06 Co 0.11 O 2 and Li 6 PS 5 Cl SSE composite cathode with outstanding discharge capacity of 210 mA h g -1 at 30 °C. A first cycle coulombic efficiency of >85, and >99% thereafter, was achieved despite a 5.5% volume change during cycling. A near-practical discharge capacity at a high areal capacity of 8.7 mA h cm -2 was obtained using an asymmetric anode/cathode cycling pressure of only 2.5 MPa/0.2 MPa.