Decoupling Stress Relief from Electrical Compromise via Carboxylated PMMA Nanospheres for Flexible Perovskite Solar Cells

作者：Xiang-Jin 香瑾 Du 杜, Yu-Qi 羽琪 Cui 崔, Shi-Yu 诗雨 Jiang 蒋, Cheng-Yu 承宇 Tan 谭, Chun-Jie 纯杰 Huang 黄, X. Qin 秦, R. Zhang 张, H. Wei 魏, Y. Ma 马, Y. Li 李, Hui-Jue 会觉 Wu 吴, J. Shi 石, Y. Luo 罗, D. Li 李, Q. Meng 孟 · 发表于：Chinese Physics Letters · 年份：2026 · DOI：10.1088/0256-307X/43/7/070802 · 研究领域：Physics

Flexible perovskite solar cells (f-PSCs) hold great promise for next-generation wearable electronics, portable power sources and even space power systems. However, these applications are fundamentally limited by optoelectronic degradation under mechanical strain. Although incorporating continuous polymeric networks enhances mechanical robustness, these insulating dielectric materials inevitably introduce carrier-transport barriers, leading to severe charge accumulation and a compromised fill factor (FF). Herein, we introduce 50-nm carboxyl-functionalized polymethyl methacrylate nanospheres (CPNs) to fundamentally decouple mechanical stress dissipation from interfacial carrier transport kinetics in inverted f-PSCs. Unlike continuous dielectric buffer layers, the CPNs self-assemble into a discontinuous nano-island network at the buried interface, maintaining unobstructed conductive pathways for efficient cross-interfacial charge transfer. Mechanically, the elastic nano-islands modulate the local strain field to efficiently dissipate mechanical and thermal stresses. Furthermore, the localized electrostatic field induced by the negatively charged carboxyl groups spatially repels electrons and accelerates hole extraction, profoundly suppressing non-radiative interfacial recombination. Consequently, the optimized f-PSCs achieve a power conversion efficiency exceeding 26% with a remarkably high FF of 0.845. The devices demonstrate outstanding structural and operational stability, ex...