Photovoltaic Effect in Indium(I) Iodide Thin Films

Halide semiconductors are undergoing a period of intense interest, buoyed by the outstanding optoelectronic properties of hybrid perovskites. It is worthwhile to consider whether related materials sharing unique aspects of the perovskite chemistry, such as the incorporation of metals that provide lone pair s electrons when integrated within the halide lattice, might yield semiconductors with comparable properties. One such metal that has not been widely studied in the context of photovoltaics is monovalent indium. In this work, we investigate a method of depositing films of indium(I) iodide, coupled with optoelectronic characterization and incorporation of these films into thin-film solar cells. We find that, although indium(I) iodide exhibits a photovoltaic effect, it is likely to be compromised by difficult-to-remove defects, e.g., iodine vacancies, which are expected to introduce recombination centers deep within the band gap.