The effect of ZnS buffer layer on Cu2SnS3 (CTS) thin film solar cells performance: Numerical approach

Abstract

The aim of this paper is to optimize a new structure of Cu2SnS3 (CTS) thin-film based solar cells by using the one-dimensional solar cell capacitance simulator (SCAPS 1D). We proposed ZnS as a non-toxic buffer layer and ITO as a window layer, neither of which has been reported with a CTS absorber layer. The effects of various parameters that affect CTS thin-film solar cell performance, such as thickness of the absorber layer, carrier concentration, band gap, and temperature, are investigated. The generation and recombination rates in both structures, Mo/CTS/ZnS/ITO and Mo/CTS/CdS/ITO, are studied. The results reveal that solar cell performance is enhanced within the range of 5e+16–2e+17 cm−3 of carrier concentration and 1.3–1.5 eV of band gap of CdS. The recombination rate at the CTS/ZnS interface is significantly lower compared to the CTS/CdS interface, indicating good conduction band alignment between the CTS absorber and ZnS buffer. Under the optimum parameters, power conversion efficiency (PCE) of CTS-based solar cells was boosted from 16.53% to 17.05% when ZnS was used as a buffer layer instead of CdS.