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Antimony selenide (Sb2Se3) is regarded as an excellent photovoltaic absorber material due to its suitable bandgap, large light absorption coefficient, abundant raw material reserves, and environmental friendliness. However, the commonly used rapid thermal evaporation strategy for deposition of Sb2Se3 films results in low film quality, which is undesirable from the perspective of photovoltaic performance. Herein, we fabricate highly efficient and stable Sb2Se3 solar cells via a close-space sublimation (CSS) process, which allows separate control of the source and substrate temperatures, leading to high-quality thin films and better solar cell performance. Four growth patterns of Sb2Se3 thin films are optimized by controlling the source temperature of CSS. It is found that the Sb2Se3 thin film prepared at 475 °C has the best crystallinity, smoothest surface, and best density. Moreover, solar cells based on ZnO/Sb2Se3 thin films can achieve maximum efficiency with VOC of 0.312 V, JSC of 27.91 mA/cm2, fill fact of 41.35%, and power conversion efficiency of 3.61%. The performance of the devices was not adversely affected by the air environment, and thus, they were shown to exhibit appropriate stability. [ABSTRACT FROM AUTHOR]

Abstract: The band structure, electronic and optical properties of Zn1− x Cr x S (x =0–1) are studied by spin-polarized first-principle calculations. The results show that Zn1− x Cr x S display half-metallic characteristics. The band gap of minority spin increases from 2.098eV to 3.98eV with Cr component, while the half-metallic gap decreases from 0.992eV to 0.548eV. Both the static dielectric constant and static refractive index increase with Cr component, but the increment is slowed down for Zn0.5Cr0.5S as a result of lowered crystal symmetry. New absorption peaks appear in the energy range of 0–2.83eV and 38.45–65.04eV due to doped Cr, moreover, the peak intensity is enhanced with the increasing Cr component and the absorption peaks have a blue shift slightly. The extinction coefficient in the energy range of 2.83–20eV decreases with the increase of Cr component. The results provide useful theoretical guidance for the application of Zn1− x Cr x S in optical detectors and spintronics. [Copyright &y& Elsevier]

In this work, HfO x /HfO 2 homo-bilayer structure based resistive random access memory devices were fabricated, and the resistive switching characteristics of the devices were investigated. The samples with an Ar/O 2 ratio of 12 : 2 exhibited improved switching performance including better uniformity, endurance and retention, which was selected to imitate the "learning" and "forgetting" function of biological synapses. The multilevel conductance of the HfO x /HfO 2 homo-bilayer structure under the model of pulse voltage suggests its potential to emulate the nonlinear transmission characteristics of the synapse, and a model of multilevel conductance of the HfO x /HfO 2 homo-bilayer structure was proposed. The device conductance continuously increases (decreases) in accordance with the number of positive (negative) voltage pulses during the potentiation (depression) process, which can emulate the change of synaptic weight in a biological synapse., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)