High Performance Perovskite Solar Cells Based on Multifunctional Additives of Crown‐Ether‐Iodine Supra‐Molecules

Abstract The efficiency and stability of perovskite solar cells (PSCs) are influenced by various factors, such as controlling the migration of iodide anion (I − ) and lithium cation (Li + ), oxidizing the hole‐transport material of 2,2′,7,7′‐tetras( N , N ‐p‐methoxyaniline)‐9,9′‐spirodifluorene (Spiro), and passivating the perovskite film. Herein, three multifunctional crown‐ether‐iodine (crown‐ether‐I 2 ) supra‐molecules are investigated as activities in the hole transport layers (HTLs). Results indicate that the crown‐ether‐I 2 can slowly release I 2 to gently oxidize Spiro, and significantly improve the efficiency of PSCs. Moreover, the crown‐ether can contribute to stabilizing Li + in HTL and passivating the defect sites on the upper interface of the perovskite layer, which can enhance the long‐term stability of PSCs. Furthermore, crown‐ether‐I 2 can absorb I − to produce crown‐ether‐I 3 − , which can discharge I − to promote the self ‐ healing of I − defects and inhibit the migration of I − in the perovskite film, thereby further enhancing PSC's long‐term stability. PSC based on Dbenzo‐24‐Crown‐8‐Ether‐Iodine (DB24C8‐I 2 ) achieves an impressive efficiency of 24.29%, which is much higher than that of the control device (22.28%). Additionally, the stability of the un‐encapsulated PSC with DB24C8‐I 2 is significantly enhanced, while maintaining 96.9% of its original efficiency after 2000 h. This work provides an effective strategy for improving the efficiency and long‐term stability of PSCs.