Theoretical screening of lead-free hybrid organic–inorganic halide double perovskites for solar cells

Abstract

Perovskite solar cells (PSCs) have attracted extensive attention due to their high efficiency and low manufacturing cost, but their practical applications are hindered by the poor structural stability and the toxicity of the heavy metal lead. In this work, we present a comprehensive study on the screening of lead-free hybrid organic–inorganic halide double perovskites (OIHDPs) by first-principles calculations. Based on theoretical evaluations of multilevel performance indicators, including tolerance factor, band gap, decomposition enthalpy, effective mass, and light absorption, we finally screened out 3 lead-free OIHDPs with FAPbI₃-comparable performance, namely FA₂AgAuBr₆, MA₂AgAuCl₆ and MA₂AgAuBr₆. Noticeably, they exhibit appropriate band gaps, low carrier effective masses, and excellent photovoltaic absorption performance, which are promising candidates for replacing the lead-based photovoltaic absorber in perovskite solar cells. Our work provides a helpful theoretical guideline for the experiment and accelerates the discovery of environment-friendly candidates for photovoltaic devices.