CuSbS₂ Solar Cells Using CdS, In₂S₃ and the In/Cd-based Hybrid Buffers

CuSbS₂, a ternary I–V–VI₂ chalcogenide material, has recently drawn great attention for use as a promising light absorber for photovoltaics. However, the low open circuit voltage (V_OC) remains as a bottleneck for CuSbS₂ solar cells which is the limitation of its power conversion efficiency. This could be caused by the severe recombination losses at the interface between CuSbS₂ and CdS buffer layers. This work aims to explore the effect of CdS, In₂S₃, and the In/Cd-based hybrid buffer layers on the device performance of CuSbS₂ solar cells. Device parameters, such as current density-voltage (J–V) and spectral response, were measured and compared, band alignment was extrapolated for CuSbS₂ with different buffer materials. With the highest measured V_OC and short circuit current density (J_sc), reduced series resistance (R_s) and improved shunt resistances leading to the highest fill factor (FF), it has been concluded that the CuSbS₂ device with combined CdS/In₂S₃ buffer layers exhibits the best performance compared to those with other buffer layers.