Selenization effects on photovoltaic properties of spray pyrolyzed CuInS2, and CuInS2/In2S3 bi-layer

Abstract

Current methods for fabricating a CuInSxSe2-x solar cell have proven costly and sometimes require toxic chemicals and methods such as KCN etching and H2Se selenization. Spray pyrolysis has been deemed as one of the cheapest and easiest method of fabricating a solar cell, but is limited by small grain sizes which limit efficiency. Presented is a method of obtaining large grains via spray pyrolysis of a CuInS2/In2S3 bi-layer and selenization using Se vapour, while showing the effects on photovoltaic parameters of a solar cell.

Effects of spray pyrolysis parameters were observed on glass substrates, following which selenization of a CuInS2/In2S3 bi-layer was performed. Full devices were fabricated on ITO, FTO and Molybdenum substrates. Selenization of a CuInS2/In2S3 bi-layer on FTO substrate was performed to demonstrate the positive effects of grain growth and photovoltaic properties of a cell.

The larger grains observed on the FTO substrates also showed improvements in cell parameters as compared to the un-selenized absorber layers on ITO. Selenization of CuInS2 layer was done on Molybdenum and a device was fabricated with efficiencies of 3.47%. This paves the way for promoting spray pyrolysis and selenization of a CuInS2/In2S3 bi-layer as a feasible process for the fabrication of a solar cell, avoiding toxic processes such as KCN etching and an alternative use of Se vapour as opposed to H2Se gas for selenization.