Theoretical investigations on enhancement of photovoltaic efficiency of nanostructured CZTS/ZnS/ZnO based solar cell device

We report a model of CZTS/ZnS/ZnO nanorod device designed using optical coefficients of each thin film layers obtained from the experimental results. The J-V\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$J-V$$\end{document} characteristic was compared with available experimental result in order to validate our model. In this model, we have examined the effect of thickness of each material layer, CZTS minority carrier lifetime, CZTS acceptor concentration, shallow and deep states formed during the fabrication process on the photovoltaic device parameters. The thickness of the CZTS absorber, buffer and window layer are optimized using optoelectronic simulations and the optimum thicknesses are found to be 2.5–3.0 µm, 30 nm and 500 nm respectively. Also, we analyzed the effect of shallow states and deep states in CZTS and ZnO layer on the photovoltaic parameters of the solar cell. After optimization of the above mentioned parameters, it is observed that the efficiency of the solar cell is improved from 3.69 to 7.65%.