Buried Interface Engineering with Multifunctional Self-Assembled Monolayers Additive Enabling Efficient and Stable Inverted Perovskite Solar Cells

The surface microstructure control and coverage of self-assembled monolayers (SAM) have made tremendous impact on the device performance and interface stability in inverted perovskite solar cells (PSCs). The integration of protonated methionine (Met+) into carbazole-based SAM (Me-4PACz) effectively drives the average particle size from 526 to 159 nm. Such an interfacial engineering strategy addresses the challenge of SAM aggregation and improves its wettability by varying the crystallization process of perovskite films. Except the macroscopic control over morphology, the graft of multiple electron-donating units including −NH3+, −COOH, and −S– into conjugated backbone could cause favorable changes in energy level alignment and reinforce its binding with NiOX substrates. Meanwhile, dangling bonds of the buried interface of the perovskite interface and the metallic Pb signals have been efficiently inhibited. The optimized PSCs achieve a power conversion efficiency of 26.31% with a fill factor (FF) of 85.97%. A well-acceptable stability has been realized, and the unencapsulated device maintains 93% of its initial efficiency after 1000 h of dark storage. This work provides novel design principles for multifunctional interfacial modifiers and establishes a crucial technical pathway for perovskite solar cell industrialization through a multicomponent cooperative passivation strategy.