Imidazole Derivative Assisted Crystallization for High-Efficiency Mixed Sn-Pb Perovskite Solar Cells

Mixed Sn-Pb perovskites with narrow bandgaps and high optical absorption coefficients are promising photovoltaic materials. However, the easy oxidation of Sn2+ and fast crystallization of mixed Sn-Pb perovskites still limit the efficiency of mixed Sn-Pb perovskite solar cells (PSCs). Here, an imidazole derivative 2-(Aminomethyl)imidazole dihydrochloride (2-AD) to suppress the oxidation of Sn2+ and improve the perovskite film quality through coordination with Sn2+/Pb2+ ions is introduced. The optimized devices show a high power conversion efficiency of 22.31% with outstanding long-term illumination stability. This work provides an effective strategy to achieve efficient and stable mixed Sn-Pb PSCs. Imidazole derivative 2-(Aminomethyl)imidazole dihydrochloride (2-AD) is introduced into Sn-Pb mixed perovskite to prepare Sn-Pb mixed PSCs. The lone pair electron of nitrogen can coordinate with metal ions to regulate the crystallization process and Cl- anion can passivate defects by forming Pb/Sn-Cl bondings. The optimized devices show a high power conversion efficiency of 22.31% with outstanding long-term illumination stability.image

Automated summary

In this work, an effective strategy to achieve efficient and stable mixed Sn-Pb perovskite solar cells (PSCs) is introduced by using imidazole derivative 2-(Aminomethyl)imidazole dihydrochloride (2-AD) to suppress the oxidation of Sn2+ and improve the perovskite film quality. The optimized devices show high power conversion efficiency and outstanding long-term illumination stability.