Molecular-Ink Based Solution Processing for Ultrahigh Light Absorption Coefficient AgBiS2 and Chalcogenide Perovskite BaZrS3

Solution processing to fabricate metal chalcogenide thin films has gained considerable interest because of its low cost and scalability. Among the various types of solution processing, homogeneous molecular ink-based processes can lead to high-quality metal chalcogenide thin films, a prerequisite for high-efficiency solar energy conversion devices. In this talk, our group’s recent works on molecular-ink derived AgBiS2 and BaZrS3 light absorbers will be presented.<br/>AgBiS2 is an attractive light absorber owing to its high light absorption coefficient over 10⁵ cm-1. An intriguing feature of this material is the change in the light absorption coefficient depending on the transition of cation order to disorder. We developed a strategy for controlling the cation disorder in AgBiS2 thin films, by carefully controlling the coordination chemistry in the Ag and Bi containing molecular inks.<br/>BaZrS3, which has the perovskite crystal structure, is an emerging light absorber that has attractive properties. However, the required temperature (~1000 oC) for the preparation of BaZrS3 is a major bottleneck for BaZrS3 to be applied to solar energy conversion devices. A novel molecular-ink based method for preparing BaZrS3 with a moderate temperature will be presented in this talk.