Photovoltaic Performance Enhancement of PerovskiteSolar Cells Using Polyimide and Polyamic Acid as Additives

Poly(amic acid) (PAA) and polyimide (PI) can interact with Pb2+ and methylammonium halide by forming Lewis acid–base adducts and hydrogen bonds, respectively. These interactions can passivate perovskite (PVSK) defects and enhance PVSK solar cell (PSC) performance. Here, PAA and PI polymers were used as PSC additives by using p-i-n PSC [ITO/NiOx/CH3NH3PbI3/with or without PAA or PI/PC61BM/BCP/Ag], and PVSK’s interactions with PAA or PI were explored through X-ray photoelectron, UV–visible, photoluminescence (PL), and time-resolved PL spectroscopies. In additive-derived PVSKs, defects passivation increased PL intensity and carrier lifetime. Field emission scanning electron microscopy revealed increased grain size, suggesting decreased grain boundary defects in PAA-derived PVSK. Moreover, 0.0497 mg/mL PAA/PVSK had high power conversion efficiency (14.16% ± 0.54% in control devices vs 16.80% ± 0.63%; highest = 17.85%). PAA/PVSK displayed excellent shelf life stability, with efficiency maintained at 16.57% ± 0...