Improvement of sprayed CuZnS/In2S3 solar cell efficiency by making multiple band gap nature more prominent.

CuZnS is a new promising material in thin film photovoltaics which is earth abundant and eco-friendly. Its electrical and optical properties can be controlled by varying atomic ratios of Copper and Zinc, so as to use it as absorber or window layers. Type of conductivity of this material can also be changed from n to p by adjusting Cu/Zn value. In the present work, we report improvement of cell parameters of CuZnS/In₂S₃ hetero junction considerably from our own earlier reported values just by increasing Cu to Zn ratio in CuZnS. Current density increased from 5.4 mA/cm² to 10.7 mA/cm², thereby enhancing conversion efficiency from 1% to 1.95%. Results are explained on the basis of improvement of multiple band structure. [ABSTRACT FROM AUTHOR]