Wavelength-dependent J-V characteristics of CuIn1-xGax(S,Se)2 solar cells and carrier recombination

Abstract

We propose here a new experimental setup, allowing the probing of CuIn1-xGax(S,Se)2 (CIGSSe) solar cells under varying wavelengths and intensities, using a supercontinuum laser. The setup is used to study the effects of potassium treatment on CIGSSe cells. Their J-V characteristics are taken at 500 nm and 950 nm, at intensities from 5 ×1014 photons cm-2 s-1 to 4 ×1016 photons cm-2 s-1. The untreated sample's response shows strong dependence on the exciting wavelength. After potassium treatment, this dependence is a lot less important. Using simulation, we show that this difference can be explained by a reduction in the defect density in the depletion region.