Achieving over 18 % Efficiency Organic Solar Cell Enabled by a ZnO-Based Hybrid Electron Transport Layer with an Operational Lifetime up to 5 Years

Although organic solar cells (OSCs) have delivered an impressive power conversion efficiency (PCE) of over 19 %, most of them demonstrated rather limited stability. So far, there are hardly any effective and universal strategies to improve stability of state-of-the-art OSCs. Herein, we developed a hybrid electron-transport layer (ETL) in inverted OSCs using ZnO and a new modifying agent (NMA), and significantly improved the stability and PCEs for all the tested devices. In particular, when applied in the D18 : N3 system, its inverted OSC exhibits so far the highest PCE (18.20 %) among inverted single-junction OSCs, demonstrating an extrapolated T₈₀ lifetime of 7572 h (equivalent to 5 years under outdoor exposure). This is the first report with T₈₀ over 5000 h among OSCs with over 18 % PCE. Furthermore, a high PCE of 16.12 % can be realized even in a large-area device (1 cm²). This hybrid ETL strategy provides a strong stimulus for highly prospective commercialization of OSCs.