The potential of amine-thiol based solution processing for chalcogenide photovoltaics

Recently it has been found that amine-thiol mixtures can dissolve many more precursors that could not be dissolved earlier. This has provided us a versatile method to prepare an array of molecular precursor inks and solution processed fabrication of metal chalcogenide thin films. This solvent mixture possesses the remarkable ability to dissolve a wide range of metal and chalcogen precursor materials under ambient temperature and pressure. Here we demonstrate the potential of the films prepared by this solvent system for photovoltaics by reporting our current amine-thiol solution processed solar cell devices with total area efficiencies of 12.20 % for Cu(In, Ga)Se₂ (CIGSe) and 7.86% for Cu₂(Zn, Sn)(S, Se)₄ (CZTSSe). For amine-thiol processed solar cells, these are the highest reported efficiencies. We also discuss the absorber layer morphology and associated optoelectronic properties. In spite of some initial challenges with solution processing, this technique has the tremendous potential for the fabrication of high-performance devices.