batteries based on Li (Na) metal as the anode material, such as Li (Na)-S and Li (Na)-O 2 batteries. [6][7][8][9][10] The specific capacities of lithium and sodium metal can be up to 3860 and 1166 mA h g −1 , respectively, much higher than that of the graphite (372 mA h g −1 ) in the traditional Li-ion batteries (LIB) and also higher than that of zinc, lead, and cadmium. [3,11,12] Therefore, Li (Na) metal can be viewed as a promising anode material candidate for the next-generation secondary batteries. Unfortunately, commercialization of the secondary Li (Na) metal battery still faces many challenges, including the volumetric change of Li (Na) metal during charging and the complex physical and chemical reactions at the interface between Li (Na) metal and electrolyte, resulting in low Coulombic efficiency and growth of dendrites. [13][14][15][16] As a result, it is critical to search for the suitable protective films (PFs) with high ionic conductivity and excellent mechanical performance, in order to improve the electrochemical properties and suppress dendrite formation.Many strategies have been carried out to modify the nanoscale interphase between Li (Na) metal anode and electrolyte for improving performance of Li (Na) metal anode. Moreover, various kinds of external protection methods have developed including, inorganic or organic molecules coating, all-solid-state Rechargeable batteries based on lithium (sodium) metal anodes have been attracting increasing attention due to their high capacity and energy density, but the implementation of lithium (sodium) metal anode still faces many challenges, such as low Coulombic efficiency and dendrites growth. Layered materials have been used experimentally as protective films (PFs) to address these issues. In this work, the authors explore using first-principles computations the key factors that determine the properties and feasibility of various 2D layered PFs, including the defect pattern, crystalline structure, bond length, and metal proximity effect, and perform the simulations on both aspects of Li + (Na + ) ion diffusion property and mechanical stability. It is found that the introduction of defect, the increase in bond length, and the proximity effect by metal can accelerate the transfer of Li + (Na + ) ion and improve the ionic conductivity, but all of them make negative influences on the stiffness of materials against the suppression of dendrite growth and weaken both critical strains and critical stress. The results provide new insight into the interaction mechanism between Li + (Na + ) ions and PF materials at the atomic level and shed light onto exploring a variety of layered PF materials in metal anode battery systems.

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For high-efficiency perovskite solar cells (PSCs), interface engineering becomes critical for carrier collection from the active perovskite material to the transport layer. To enhance the power conversion efficiency (PCE), herein we demonstrate a novel method named surface plasma treatment on a mesoporous TiO electron-transport layer (ETL) to improve electron extraction and transport properties at the perovskite/TiO interface. According to the XPS results, the plasma treatment induced a partial reduction of Ti to Ti within the TiO lattice and increased the concentration of oxygen vacancies on the TiO surface. Ultraviolet photoelectron spectra (UPS) show that the Fermi level of TiO upshifts about 0.2 eV which may effectively promote carrier separation and transfer at the perovskite/TiO interface. In addition, these created donor levels of Ti and oxygen vacancies donate extra electrons, increasing the conductivities of TiO films and which could further promote transport. The time-resolved photoluminescence spectra (TRPL) confirm that the decay time decreases dramatically from 656 ns to 235 ns after 90 s plasma treatment, which indicates a more efficient electron-transfer process. Based on all the above-mentioned results, a remarkable enhancement in cell efficiency was obtained, such that the average efficiency was improved from 11.5 % to 14.3 % under AM 1.5G irradiation (100 mW cm ).

Cs 3 Bi 2 I 9 (CBI) single crystal (SC) is a promising material for a higher-performance direct X-ray detector. However, the composition of CBI SC prepared by the solution method usually deviates from the ideal stoichiometric ratio, which limits the detector performance. In this paper, based on the finite element analysis method, the growth model of the top-seed solution method has been established, and then the influence of precursor ratio, temperature field, and other parameters on the composition of CBI SC has been simulated. The simulation results were used to guide the growth of the CBI SCs. Finally, a high-quality CBI SC with a stoichiometric ratio of Cs/Bi/I = 2.87:2:8.95 has been successfully grown, and the defect density is as low as 1.03 × 10 9 cm −3 , the carrier lifetime is as high as 16.7 ns, and the resistivity is as high as 1.44 × 10 12 Ω•cm. The X-ray detector based on this SC has a sensitivity of 29386.2 μC•Gy air −1 cm −2 at an electric field of 40 V•mm −1 , and a low detection limit of 0.36 nGy air •s −1 , creating a record for the all-inorganic perovskite materials.

The performance of CdS/CdSe/CdTe devices is related to the conduction band offset of CdSexS1−x/CdTe layers on CdTe solar cells.