GeSe-based hole transport layer for efficient Cu2CdSnS4 heterojunction solar cells: A simulation approach

Abstract

Copper cadmium tin sulfide (CCTS) (Cu2CdSnS4) is an effective quaternary semiconductor absorber material for solar photovoltaic cells. This study employed solar photovoltaic cell capacitance emulation (SCAPS-1D) in order to numerically evaluate the effectiveness of the heterojunction structure (AZO/ZnxCd1-xS/CCTS/MO). aluminum-doped zinc oxide (ZnO:Al or AZO), Various buffer layer compositions (ZnxCd1-xS) were examined without a back surface field (BSF) (GeSe). A novel buffer layer (Zn0.2Cd0.8S) emerged with superior photovoltaic characteristics (open-circuit voltage Voc, fill factor FF, Short circuit current Jsc, power conversion efficiencies PCE) compared to the existing buffer layers (Zn0.05Cd0.95S, Zn0.08Cd0.92S, Zn0.1Cd0.90S, Zn0.2Cd0.8S, Zn0.3Cd0.7S, Zn0.5Cd0.5S, Zn0.6Cd0.4S, and Zn0.8Cd0.2S).Subsequently, the performance of single-layer (MO/CCTS/Zn0.2Cd0.8S/AZO) and dual-layer (MO/GeSe/CCTS/ Zn0.2Cd0.8S/AZO) structures was compared. The optimal thicknesses for the layer of absorbtion (CCTS) and buffer layer (Zn0.2Cd0.8S) were 2.1 and 0.1 μm, respectively. The incorporation of a)GeSe(layer further enhanced the device's overall efficiency. The optimal interface defect densities were interface defect density of Zn0.2Cd0.8S/AZO = 1016 cm−2, of CCTS/ Zn0.2Cd0.8S = 1014 cm−2, and of GeSe/CCTS 1014 cm−2. The bestead work function for the ahead connect was 4.5 eV or lower, while the optimal work function for the connection at the back was 5.15 eV. With these optimized parameters, the photovoltaic device accomplished a power conversion effectiveness (PCE) of 26.58 %, highlighting the promising potential of the CCTS-based photovoltaic devices for an efficient solar energy conversion.