Cu(In,Ga)Se2 absorbers prepared by electrodeposition for low-cost thin-film solar cells

Abstract

Reducing the manufacturing cost of solar cells is necessary to their industrial production. Electrodepositing is an effective, non-vacuum method which is very suitable for cutting the manufacturing cost of thin films as well as developing its large-scale industrial production. In this study, about 1-μm-thick Cu(In,Ga)Se2 (CIGS) precursors were electrodeposited on Mo/glass substrates in aqueous solution utilizing a three-electrode potentiostatic system. Triethanolamine was used as complexing agent, and all parameters of electrodeposition were precisely controlled. After that, the electrodeposited precursors were selenized in a Se atmosphere with different heating ramp rates (60 and 600 °C·min−1). High-quality CIGS films were obtained, and their characteristics were investigated by X-ray fluorescence, scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, Raman spectra and near-infrared–visible (NIR-Vis) spectra. The results reveal that there are many differences between the properties of the films under different heating rates. Finally, CIGS solar cells were fabricated using a fast and a slow heating rate. The maximum efficiencies achieved for the films selenized at 60 and 600 °C·min−1 are 3.15% and 0.71%, respectively.