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CuSbSe2 is emerging as a potential absorber layer for thin-film photovoltaics, due to its attractive photovoltaic properties, environmental friendliness and its earth-abundant constituent elements. CuSbSe2 thin films were deposited by a thermal-evaporation technique with three different compositions, namely, Cu-rich, Cu-poor and near-stoichiometric. The stoichiometric CuSbSe2 thin film was annealed at 400 °C. Compositional, structural, morphological and optical properties of CuSbSe2 thin films were investigated by energy-dispersive X-ray spectroscopy, X-ray diffraction (XRD), atomic-force microscopy and ultraviolet/visible/near infrared (UV/VIS/NIR) spectroscopy. XRD spectra show that CuSbSe2 phases are always present, regardless of the elemental compositions of the deposited films. All prepared film absorbed significantly in the visible region. The absorption coefficient—of all samples—was greater than 105 cm−1. The optical band gap was estimated to be 1.44 eV for near-stoichiometric deposited film and was decreased to 1.2 eV after annealing at 400 °C. Thus, stoichiometric CuSbSe2 thin film can be obtained at room temperature using a thermal-evaporation technique, and the quality and crystallinity of the film can be improved with annealing. [ABSTRACT FROM AUTHOR]

Achieving high-performance perovskite solar cells with satisfactory efficiency requires a decrease of charge carrier recombination and intrinsic density of defects in organic and inorganic halide perovskite absorber materials. In this study, the effect of vanadium copper sulfide (VCuS) nanoparticles (NPs) used to accelerate CH3NH3PbI3 perovskite crystallization in a single phase is investigated. The results indicate that the employed VCuS NPs influence the purity, formation of a single phase, and crystallinity of CH3NH3PbI3 perovskite with favorable crystal growth in the (110) direction. The morphological analysis indicates the existence of a dense, compact, and homogeneous structure, which is associated with a large grain size that extends the lifetime and reduces recombination by increasing the electron-hole diffusion length. According to its optical characteristics, perovskite has an energy gap between 1.62 and 1.6 eV for visible light and an absorption coefficient in excess of 105 cm− 1. Photoluminescence (PL) measurements revealed that when VCuS NPs were added to perovskite thin films, the PL intensity decreased, indicating a decrease in charge recombination. For sample 8 mg/mL-VCuS, the bulk heterojunction solar cells demonstrated a power conversion efficiency (PCE) of 15.11%, a short-circuit current density (Jsc) of 20.93 mA/cm2, an open-circuit voltage (Voc) of 1.043 V, and a fill factor (FF) of 69.23%. In addition to enhancing light harvesting efficiency, this superior doped perovskite film eliminates pinholes, which reduces charge recombination in solar cells. [ABSTRACT FROM AUTHOR]