Surface Reconstruction of a Perovskite Film by an Organic Salt for High-Performance Solar Cells with Improved Stability.

Organic-inorganic lead halide perovskites have undergone tremendous development due to their excellent optoelectrical properties, achieving exceptional photovoltaic performance up to over 25%. The interface engineering method has a significant role in further improving the perovskite solar cell performance to its limit. Herein, we fabricated a modified GAMAPbI perovskite film using the organic amine small molecule 3-(aminomethyl)pyridine (3AP), which increased the grain sizes and crystallinity through the modulated melting process as well as reacted with the surface component, especially the defect site of the PbI octahedral layer, resulting in a high-quality perovskite film. The perovskite films without (pristine) and with toluene were also fabricated to prove the significant role of the 3AP organic molecule. The 3AP-modified GAMAPbI perovskite film exhibits a long carrier lifetime and suppresses the charge recombination loss, resulting in an increased fill factor (FF) of 75.66% and a power conversion efficiency (PCE) of 17.28%, which are higher than those of pristine (FF, 66.36%; PCE, 14.06%) and toluene-treated perovskite devices (FF, 72.40%; PCE, 16.84%). More importantly, the 3AP-modified perovskite device shows remarkable environmental stability to the ambient conditions, with the PCE retaining 92% of the initial PCE for over 1000 h under ambient conditions.