Numerical simulation of non-toxic In2S3/SnS2 buffer layer to enhance CZTS solar cells efficiency by optimizing device parameters

CZTS solar device is simulated using SCAPS-1D software to investigate In2S3 and SnS2 semiconductors as the potential buffer layer. Both Indium sulphide (In2S3) and tin sulphide (SnS2) exhibit good conductivity, optimum bandgap, and optical transparency towards shorter wavelength, which are quite suitable traits for buffer layer material. As these compounds are non-toxic, they seem to be the good replacement for conventional, efficient and yet highly toxic CdS material. The substrate cell structures n-ITO/i-ZnO/In2S3/CZTS/MoS2/Mo and n-ITO/i-ZnO/SnS2/ CZTS/MoS2/Mo are used as the base model in this study. For both the buffer layers, results are optimized by following a valid procedural approach. The optimized efficiencies are 19.03 % and 18.94 % for In2S3 and SnS2 based buffer layers solar cell, respectively. The comparative analysis of this result with other reported works reflects promising prospects.