A brief review on the lead element substitution in perovskite solar cells

Organic-inorganic halide perovskites have attracted huge attentions as the novel photoelectric function materials. So far, perovskite solar cells (PSCs) with prominent performance are still based on the lead halide perovskites, although they are potentially highly toxic. The issue of toxicity has become one of most crucial problems before its commercialization. Therefore, an increasing number of studies have focused on the lead element substitution in PSCs, and many excellent achievements have been reported. Alternative elements, e.g., Sn, Ge, Bi and Sb were successively used to fabricate lead-free perovskites, which provided potential possibility to tackle the toxicity issue. Recently, Sn-Pb hybrid perovskites were demonstrated to realize lead reduction without sacrificing the PCE. In addition, a new family of halide double-perovskites was explored and given high expectations. Here, we give a brief review on the lead substitution in PSCs, including theoretical explorations and experimental achievements, and finally we propose some perspectives.