Efficient and Endurable Flexible Carbon‐Electrode Perovskite Solar Cells Enabled by Strain Compensation Strategy

Abstract Flexible carbon‐electrode perovskite solar cells (F‐CPSCs) featuring cost‐effectiveness, lightweight, and environmental robustness have aroused considerable attention for portable power source applications. However, the photovoltaic performance of F‐CPSCs is still unsatisfactory, with a recorded efficiency of less than 18%. Herein, a strain compensation strategy by depositing the hot solution of hole transport material (HTM) upon the perovskite film is proposed. Noted that the developed strategy not only transforms the detrimental tensile strain into the benign compressive strain for perovskite film, but also optimizes interfacial energy level alignment, facilitates ordered molecular arrangement of HTM, and endows strong defect passivation toward perovskite film. The overall results suppress the non‐radiative charge recombination, accelerate hole extraction and transport, and impart better protection toward the perovskite film. Consequently, the target rigid C‐PSCs and F‐CPSCs present a promising efficiency of 20.91% and 19.52%, respectively. Besides, the target F‐CPSCs deliver respectable durability against moisture, light, and mechanical bending. Especially, the target F‐CPSCs can preserve 75.06% of their initial efficiency after undergoing mechanical bending with a curvature radius of 8 mm for 1000 cycles, much better than the control ones (42.70%). This work provides a facile yet efficient approach to developing efficient and endurable F‐CPSCs.