A Nonvacuum Approach for Fabrication of Cu₂ZnSnSe₄/In₂S₃ Thin Film Solar Cell and Optoelectronic Characterization

Abstract

Cd-free kesterite-based Cu2ZnSnSe4 (CZTSe)/In2S3 champion solar cell of 5.74% efficiency has been fabricated by chemical spray pyrolysis. In this fabrication route, CZTSe absorber layer was sprayed by using a precursor solution, where metallic salts were dissolved in water-based solvent and subsequently selenized with Se powder at high temperature. In2S3 buffer as an alternative to CdS buffer was also deposited by chemical spray pyrolysis. The device characteristics were studied by measuring dark/light illuminated J–V–T, external quantum efficiency, temperature dependence of open circuit voltage (VOC) and series resistance (Rs), and admittance spectroscopy. The performance of sprayed CZTSe/In2S3 solar cell was found to be limited by high back-contact barrier potential, poor carrier collection, and detrimental intrinsic defect states in device.