Prospects of lead-free perovskite-inspired materials for photovoltaic applications

With hybrid lead halide perovskites, a new class of materials for photovoltaics emerged, approaching GaAs in their optoelectronic properties. However, issues concerning toxicity and instability of lead-based perovskites impede their commercialization. Therefore, alternative lead-free solution-processable semiconductors have attracted increasing attention. The focus is mainly on compounds with structural similarities to the three-dimensional network of the lead halide octahedra in the perovskite structure. Furthermore, additional metal halides or chalcogenides have emerged with non-perovskite-related crystal structures but promising physical properties. This review will discuss recent progress on lead-free perovskite-inspired materials suitable for optoelectronics, considering their structure as well as their physical properties and resulting implications for device applications.