24% Efficient, Simple ZnSe/Sb ₂Se ₃ Heterojunction Solar Cell: An Analysis of PV Characteristics and Defects

Abstract

In this work, a new wide-band-gap n-type buffer layer, ZnSe, has been proposed and investigated for an antimony selenide (Sb ₂Se ₃)-based thin-film solar cell. The study aims to boost the Sb ₂Se ₃-based solar cell’s performance by incorporating a cheap, widely accessible ZnSe buffer layer into the solar cell structure as a replacement for the CdS layer. Solar Cell Capacitance Simulator in One Dimension (SCAPS-1D) simulation software is used to thoroughly analyze the photovoltaic parameters of the heterojunction structure ZnSe/Sb ₂Se ₃. It includes open circuit voltage ( V _OC), short-circuit current density ( J _SC), fill factor (FF), power conversion efficiency (PCE), and external quantum efficiency (EQE). The absorber layer (Sb ₂Se ₃) thickness is adjusted from 0.5 to 3.0 μm to perfect the device. In addition, the influence of cell resistances, radiative recombination coefficient, acceptor and donor defect concentration in the Sb ₂Se ₃ layer, and interface defects of the ZnSe/Sb ₂Se ₃ layer on overall device performance are investigated. The ZnSe buffer layer and the Sb ₂Se ₃ absorber layer are designed to have optimal thicknesses of 100 nm and 1.5 μm, respectively. The proposed device’s efficiency with optimized parameters is calculated to be 24%. According to the simulation results, it is possible to build Sb ₂Se ₃-based thin-film solar devices at a low cost and with high efficiency by incorporating ZnSe as an electron transport layer.