Investigation of cesium-based triple layer halide perovskites solar cell a high-performance photovoltaics

Abstract

The present study investigates the structural, optoelectronic and photovoltaic properties of cesium-based triple layer halide perovskites Cs₂SnBr₆, CsPbBr₃, and CsSnBr₃ using density functional theory (DFT) and SCAPS-1D simulation. The calculated electronic band gaps are 1.7 eV, 2.5 eV, and 1.3 eV for Cs₂SnBr₆, CsPbBr₃, and CsSnBr₃, respectively, and all three compounds exhibit direct band gaps. Their optical properties indicate robust absorption in the ultraviolet (UV) region, indicating their potential for optoelectronic applications. Subsequently, a novel triple-absorber-layer device architecture was proposed and numerically simulated. In this study, ten different device architectures were evaluated using SCAPS-1D by combining various electron transport layers (ETLs), namely WS₂, C60, LBSO, PCBM, and TiO₂ with hole transport layers (HTLs) including CBTS, CNTS, Cu₂Te, NiOₓ, and Spiro-OMeTAD. Among these, the architecture FTO/WS₂/CsSnBr₃/Cs₂SnBr₆/CsPbBr₃/CNTS/Au proved to be the most effective, yielding exceptional photovoltaic performance with a short-circuit current density (J_SC) of 30.42 mA/cm², an open-circuit voltage (V_OC) of 1.1543 V, a fill factor (FF) of 88.42%, resulting a power conversion efficiency (PCE) of 31.05%. Further analysis shows that the temperature rise leads to a decrease in the VOC and the PCE as a result of the higher reverse saturation current value and that the device efficiency can be significantly improved by increasing the shunt resistance value. This combined DFT and SCAPS-1D study gives important insights into the experimental work for the production of high-performance photovoltaic devices.