Numerical simulation and optimization of physical properties for high efficiency CuSbS2 thin film solar cells

Abstract

Here we present numerical modeling of copper antimony sulfide (CuSbS2) solar cells to analyze the impact of several interrelated physical parameters of the absorber layer and absorber/buffer interface such as bulk vs interface defect density, energy band gap vs electron affinity of CuSbS2, absorber thickness vs acceptor density together with device shunt vs series resistance on the device efficiency. A benchmark simulation of the experimental CuSbS2 solar cell is initially performed in SCAPS-1D (Solar Cell Capacitance Simulator in one dimension) environment considering a suitable defect model, which gave an efficiency of 3.19 % comparable to the experimental value. After the systematic optimization of different materials properties and interface defect density, the power conversion efficiency is increased up to 10.71 % with a remarkable upgrade in open circuit voltage, photocurrent, and fill factor. A detailed analysis of heterojunction features such as built-in potential, depletion width, diffusion length, and carrier recombination was performed to understand the impact of the aforementioned physical parameters on the performance of this solar cell. The present results give an important guideline to find out the shortcomings of CuSbS2 solar cells, which in turn help the researchers for designing and feasible fabrication of more efficient CAS solar cells.