The nonhalides in perovskite solar cells

Abstract

Recently, halide perovskite solar cells (PSCs) have accomplished the most remarkable progress in emerging photovoltaic technology. However, their poor stability hinders the route to commercialization. Notably, the high chemical activity of halides such as I⁻ and Br⁻ and the formed halide-related vacancy defects lead to the instability of PSCs. In spite of the importance of X-site anions, more and more works have been devoted to the polyatomic pseudohalides and superhalogens in perovskites. In this context, this review will focus on the basic understanding of the structural and photoelectric properties of pseudohalides and superhalogens. We comprehensively summarize the current research progress of SCN⁻, HCCO⁻, Ac⁻, BF₄⁻, BH₄⁻, and PF₆⁻ anions to realize high structurally stable perovskites and related solar cells. Based on these observations, some perspectives on future efforts toward achieving highly stable PSCs are proposed and discussed.