Ionic Liquid Stabilized Perovskite Solar Modules with Power Conversion Efficiency Exceeding 20%
Yu‐Long Wang, Yufei Yang, Neng Li, Min Hu, Sonia R. Raga, Yang Jiang, Chao Wang, Xiaoli Zhang, Mónica Lira‐Cantú, Fuzhi Huang, Yi‐Bing Cheng, Jianfeng Lu
Abstract
Abstract Metal‐halide perovskite solar cells (PSCs) exhibit outstanding power conversion efficiencies (PCEs) when fabricated as mm‐sized devices, but creation of high‐performing large‐area modules that are stable on a sufficiently long timescale still presents a significant challenge. Herein, the quality of large‐area perovskite film is improved by using ionic liquid additives via forming a new Pb‐N bonding between the ionic liquid and Pb 2+ . This new bond can be modulated by a critical screening of the anion structure of the ionic liquid. The selected ionic liquid effectively reduces the defects of the perovskite films and markedly elongate their carrier lifetimes. As a result, a champion PCE of 24.4% for small‐area (0.148 cm 2 ) devices and 20.4% for larger‐area (10.0 cm 2 ) modules under AM 1.5G irradiation is achieved. More importantly, the modified devices retain 90% of their peak PCE after aging for 1900 h at 65 ± 5 ° C (ISOS‐T‐1) and 80% after continuous light soaking for 750 h. The non‐encapsulated modules maintained 80% of their peak PCE after 1100 h of aging in the air with a relative humidity of 35 ± 5% and temperature of 25 ± 5 ° C under dark (ISOS‐D‐1), showing great potential for future commercialization.