Revealing the Role of Bifunctional Molecules in Crystallizing Methylammonium Lead Iodide through Geometric Isomers

Multifunctional additives are widely utilized in enhancing the performance of perovskite solar cells, and the role of the additives is highly related to the contained various functional groups. Here, we introduce a pair of geometric isomers, which act as bifunctional additives with a terminal −NH3+ group and a terminal −COOH group, into methylammonium lead iodide perovskite. Surprisingly, although the two additives share exactly the same...