Regulating Strain and Suppressing Defect States Through Polymer Ionization and Chemical Chelation for Efficient Inverted Flexible Perovskite Solar Cells

Flexible perovskite solar cells (FPSCs) have great promise for applications in wearable technology and space photovoltaics. However, the unpredictable crystallization of perovskite on flexible substrates results in significantly lower efficiency and mechanical durability than industry standards. A strategy is investigated employing the polymer electrolyte poly(allylamine hydrochloride) (PAH) to regulate crystallization and passivate defect states in perovskite films on flexible substrates. The weakly acidic precursor allows PAH to undergo partial ionization, leading to the protonation of some ─NH