Impact of Amine Additives on Perovskite Precursor Aging: A Case Study of Light-Emitting Diodes

Amines are widely employed as additives for improving the performance of metal halide perovskite optoelectronic devices. However, amines well-known their high chemical reactivity, impact which has yet to receive enough attention from light-emitting diode community. Here, by investigating an unusual positive aging effect CH3NH3I/CsI/PbI2 precursor solutions example, we reveal that gradually undergo N-formylation in precursors over time. This reaction is initialized hydrolysis dimethylformamide acidic environment. Further investigations suggest products collectively crystallization and eventually lead significantly enhanced external quantum efficiency values, increasing ∼2% fresh ≳12% aged ones. While this case study provides a effect, negative possible other perovksite systems. Our findings pave way more reliable reproducible device fabrication call further underlying reactions within inks once amine included.