Tailored dual-site molecule for surface modulation of highly efficient inverted perovskite solar cells

The non-radiative recombination on the perovskite surface caused by defects has a significant impact on the photovoltaic performance of perovskite solar cells (PSCs). Here, we investigated the influence of the dual-site passivation strategy for treating the perovskite/C₆₀ interface on the performance of inverted PSCs. Theoretical calculations show that 4-(2-Aminoethyl) tetrahydropyran, HCl (4TH) tends to be horizontally arranged on the surface of perovskite, and the dual sites act simultaneously on perovskite. The experimental results show that 4TH can passivate the surface of perovskite and adjust the interface energy level. The surface of the perovskite after passivation has a more compatible energy level with C₆₀, promoting the transport of charge carriers. The power conversion efficiency (PCE) of inverted PSCs following the 4TH modification attains 25.02 %. Furthermore, the modified unencapsulated device exhibited improved long-term and thermal stability.