An N-type dimeric organic molecule as interfacial modifier for inverted perovskite solar cells

An n-type dimeric organic molecule, B2, is employed as an interfacial modifier to regulate the contact property between the perovskite layer and PCBM ETL in inverted PSCs. • B2 interlayer passivates defects in the perovskite layer and optimizes the energy level alignment at the interface. • A prominent PCE of 20.20% is delivered by PSCs with B2 as the interlayer, alongside minimal hysteresis. • The unencapsulated devices retain more than 80% of initial PCE after 1000 h in ambient humid air. Interface engineering at the perovskite/electron transport layer (ETL) junction has been demonstrated as an effective strategy for achieving high-quality interfacial contact in perovskite solar cells (PSCs). In this work, an n-type dimeric organic molecule, B2, is employed as an interfacial modifier to regulate the contact property between the perovskite layer and PCBM ETL. Experimental results reveal that the B2 interlayer passivates defects in the perovskite layer through coordination with undercoordinated Pb 2+ ions, thereby suppressing trap-assisted non-radiative recombination. Furthermore, the B2 modification optimizes the Energy level alignment at the interface, promoting efficient charge carrier transport. As a result of these synergistic effects, the interface-engineered PSCs achieve a power conversion efficiency of 20.20% and maintain over 80% of their initial efficiency after 1056 h of aging tests. This study provides an effective interfacial regulation approach for developing highly efficient and stable PSCs. Download: Download high-res image (136KB) Download: Download full-size image