Efficiency enhancement of CZTS solar cell with WO3 buffer layer using CZTSe BSF layer

Non-toxic, low-cost, and bandgap-direct material Copper Zinc Tin Sulphide (CZTS) is a promising candidate thin film solar cell. As the effort to improve the efficiency of the CZTS solar cell, this work chooses an environmentally friendly tungsten oxide (WO 3 ) as the buffer layer due to its high bandgap and excellent electrical conductivity. Furthermore, Cu 2 ZnSnSe 4 (CZTSe) is employed as the back surface field (BSF) layer which is sandwiched between the absorber layer and the back contact layer. A new structure Pt/CZTSe/CZTS/WO 3 /ZnO is proposed and a comparative study is done between structures with and without BSF layer. The research investigates how the layer thickness, operating temperature, different back contact layer, acceptors, and defects in BSF layer affect the performance of CZTS solar cell using the solar cell capacitance simulator (SCAP-1D) simulation software. Efficiency of CZTS solar cell with WO 3 is greatly improved with efficiency as high as 29.37 % for the proposed new structure.