Amidation induced self-reduction of p-GO with Lewis-base termination for all-inorganic CsPbIBr2 perovskite solar cells†

Abstract

Simultaneously tailoring the interfacial energetics and healing the defective nanostructure of perovskite films is important for promoting the power conversion efficiency of perovskite solar cells (PSCs). Herein, a fluoroaniline molecule-terminated graphene oxide (GO) is fabricated as an interface modulator in all-inorganic CsPbIBr₂ PSCs. Owing to the amidation reaction induced p–π conjugation effect with an adjacent benzene ring, the spontaneous electron transfer from oxygen-containing groups at the GO surface to the aniline unit causes the self-reduction and p-type doping of GO, benefiting hole extraction and delocalization. Together with the passivation effect by –F termination with under-coordinated Pb²⁺, the best device delivers an efficiency of 11.08% with superior stability originating from the presence of hydrophobic C–F bonds, the reduced defects and suppressed ion migration. Moreover, the functionalized GO can effectively capture and obstruct the leakage of Pb²⁺ ions from a destructive device, demonstrating its unique advantages in high-performance PSC platforms.