Dual interfacial modification with 1D perovskite for self-assembled monolayer based inverted perovskite solar cells

Recently, self-assembled monolayer (SAM) based inverted perovskite solar cells (PSCs) have been extensively studied due to their remarkable stability and compatibility with large-area devices. Microporesat the SAM/perovskite buried interface are commonly observed, which result in the increased defect density and hindered charge extraction. Herein, a multifunctional organic material, namely 2-(methylthio)-4,5-dihydro-1H-imidazole ammonium iodide (MTIm), is introduced as an interfacial modification material to react with the residual PbI2, forming one-dimensional (1D) (MTIm)PbI3 small grains. We found that the 1D perovskite distributes at both top and buried interfaces of PSC, achieving dual-interfacial passivation of defects. Moreover, the 1D perovskite leads to a favorable n-type doping at the top interface, and relaxes the lattice strain at the buried interface. As a result, the champion PSC device achieves significantly improved power conversion efficiency from 21.7% to 23.8%, and retains over 90% of its initial PCE after storing in air for 1500 hours.