Tailoring Multifunctional\nAmine Salts Based on Anisole\nLiquid Soaking for Fabricating Efficient and Stable Perovskite Solar\nCells

The post-treatment based on spin-coating (SC) organic\namine salts\nis commonly used for surface modification of perovskite films to eliminate\ndefects. However, there is still a lack of systematic study and a\nunified understanding of the functions and mechanisms of different\norganic amine salts. The SC method is also not conducive to the industrialization\nof solar cells. In this work, we study three different organic amine\nsalts, and a passivation strategy for perovskite films based on green\nanisole liquid soaking (ALS) has been developed. Phenylethylammonium\niodide (PEAI), diethylamine hydroiodide (DEAI), and guanidine hydroiodide\n(GAI) organic amine salt passivators are selected to modify perovskite\nfilms, and their effect and working mechanism are also systematically\nestimated. It is found that PEAI passivates shallow-level defects\non the surface of perovskite films, while DEAI incorporates into the\nperovskite lattice to suppress point defects, and GAI eliminates excess\nPbI<sub>2</sub> residuals in perovskite films. These three organic-amine-salt-modified\ndevices achieve enhanced power conversion efficiencies (PCE) of 21.82%\n(PEAI-ALS), 21.74% (DEAI-ALS), and 22.21% (GAI-ALS), which is much\nhigher than that of the pristine device without treatment (19.95%).\nThe PCE of the PEAI-ALS device retains nearly 94% of the initial efficiency\nafter 1200 h in unpackaged conditions and about 40% ambient humidity,\nachieving the best stability performance. Particularly, the PEAI-ALS\ndevice has the best comprehensive performance in efficiency and stability.\nAnd PEAI is estimated by the SC method and ALS method, and it is found\nthat the PEAI-ALS device achieves a higher PCE compared to the PEAI-SC\ndevice (21.51%). We believe that the post-treatment based on a combination\nof appropriate amine salts and ALS enables a universal approach for\nfabrication of perovskite solar cells with enhanced photovoltaic performance.