Synergistic dynamic bonds in self-repairing elastomers boost efficiency and bendability of flexible perovskite photovoltaics

Abstract

Perovskite materials have emerged as a hotspot in the photovoltaic field due to their excellent light absorption properties, high carrier mobility, and tunable bandgaps. However, perovskite films are prone to mechanical stress and environmental factors during long-term use, leading to performance degradation, insufficient stability, and so on. Herein, a self-healing elastomeric polyurethane (SBOPU) is introduced to repair cracks in perovskite films while simultaneously releasing residual lattice strain. The CO groups in SBOPU effectively passivate undercoordinated Pb²⁺ ions, whereas the N–H groups form hydrogen bonds with I⁻ ions in the perovskite lattice. This dual functionality not only enhances the structural integrity of the perovskite layer but also significantly improves its stability. As a result, the rigid and flexible perovskite solar cells (PSCs) modified by SBOPU fabricated fully under ambient air conditions achieved a photoelectric conversion efficiency (PCE) of 22.34% and 19.68%, respectively. Meanwhile, the f-PSCs still maintain an initial efficiency of 81.27% after 1000 cycles at a bending radius of 5 mm. Notably, after 2000 bending cycles, f-PSCs recovered to 85.30% of their initial efficiency through thermally induced self-healing. This work provides a new strategy for the development of highly durable flexible perovskite optoelectronic devices.