Reducing the Vibration of Carbazole‐Based Self‐Assembled Monolayers for High‐Performance Inverted Perovskite Solar Cells Through the Deuteration Strategy

Abstract Carbazole‐based self‐assembled small molecules are promising and commonly used hole transport layers (HTLs) materials for inverted perovskite solar cells (IPSCs). Here, a novel perdeuterated carbazole‐based SAM named 4PACzd8 is obtained. Owing to the deuteration strategy, which causes a reduction in molecular vibration frequency, 4PACzd8 modulates the perovskite crystallization atop and suppresses interfacial non‐radiative recombination. Furthermore, it is noteworthy that 4PACzd8 demonstrates heightened UV absorption properties, thereby offering enhanced protection to the underlying perovskite film from degradation resulting from UV exposure. Compared with the non‐deuterated analog 4PACz, the champion device employing 4PACzd8 showed a higher power conversion efficiency (PCE) of 24.87% and excellent stability. The impressive PCE of 24.87% is by far one of the highest values for IPSCs with simple carbazole‐based SAMs as HTLs.