Ultrathin polymer membrane for improved hole extraction and ion blocking in perovskite solar cells
Lina Shen, Peiquan Song, Kui Jiang, Lingfang Zheng, Jianhang Qiu, Fangyao Li, Yu Huang, Jinxin Yang, Chengbo Tian, Alex K.‐Y. Jen, Liqiang Xie, Zhanhua Wei
Abstract
Highly efficient perovskite solar cells (PSCs) in the n-i-p structure have demonstrated limited operational lifetimes, primarily due to the layer-to-layer ion diffusion in the perovskite/doped hole-transport layer (HTL) heterojunction, leading to conductivity drop in HTL and component loss in perovskite. Herein, we introduce an ultrathin (~7 nm) p-type polymeric interlayer (D18) with excellent ion-blocking ability between perovskite and HTL to address these issues. The ultrathin D18 interlayer effectively inhibits the layer-to-layer diffusion of lithium, methylammonium, formamidium, and iodide ions. Additionally, D18 improves the energy-level alignment at the perovskite/HTL interface and facilitates efficient hole extraction. The resulting PSCs achieve efficiencies of 26.39 (certified 26.17) and 25.02% with aperture areas of 0.12 and 1.00 square centimeters, respectively. Remarkably, the devices retain 95.4% of the initial efficiency after 1100 hours of operation in maximum power point tracking, representing significant stability advancements for high-efficiency n-i-p PSCs. The operational lifetimes of n-i-p perovskite solar cells have been limited by the layer-to layer ion diffusion in the perovskite/hole-transport layer heterojunction. Here, the authors introduce an ultrathin p-type polymeric interlayer and achieve a certified efficiency of 26.17% in stable devices.