Utilizing electrostatic dynamic bonds in zwitterion elastomer for self-curing of flexible perovskite solar cells

Summary Organometallic halide perovskites are promising candidates for high-performance flexible perovskite solar cells (f-PSCs). However, f-PSCs still face significant challenges in the formation of uniform and highly crystalline films with mechanical robustness. Here, a zwitterion elastomer (SBMA) was introduced into a perovskite film. SBMA cross-linked in situ to regulate the nucleation and crystallization of the perovskite by forming an intermediate SBMA-PbI 2 adduct. In addition, the polar sulfo-end group on SBMA offered chemical passivation to perovskite vacancies and created a large dielectric environment, screening the carrier capture process and suppressing nonradiative recombination. The zwitterionic fusion within the cross-linked elastomers, residing on grain boundaries, endowed the flexible perovskite films with instantaneous self-curing ability under mild treating conditions (40°C for 15 min). The resultant device achieved a record-breaking power conversion efficiency (PCE) of 24.51% (certified 24.04%) and demonstrated excellent mechanical sustainability and durability, retaining over 90% of the initial PCE after 10,000 bending cycles.