Cost‐Effective Transparent N‐Doped Tin Oxide Electrodes with Excellent Thermal and Chemical Stabilities Enabling Stable Perovskite Photovoltaics Based on Tin Oxide Electron Transport Layer

Abstract Perovskite solar cells (PSCs) incorporating chemical‐bath‐deposited (CBD) SnO 2 layers have garnered considerable attention because they combine high electron mobility and low‐temperature processing, affording remarkable photovoltaic performance. However, the acidic conditions of CBD limit its compatibility with front transparent electrodes (FTEs). Herein, cost‐effective, thermally stable, and highly transparent nitrogen‐doped SnO 2 (NTO) FTEs tailored to integrate with CBD‐SnO 2 ‐based PSCs are developed. By precisely controlling the N dopant content in the magnetron sputtering process, a NTO FTE with a sheet resistance of 38.64 Ω/square, an optical transmittance of 86.17%, a smooth surface morphology (1.2 nm), and mechanical flexibility is obtained. Furthermore, doping N in SnO 2 imparts thermal and chemical stability superior to those of conventional Sn‐doped In 2 O 3 (ITO) electrodes. Additionally, a well‐matched energy band of NTO with a SnO 2 electron transport layer (ETL) and homogeneous interfaces is a critical advantage. By implementing this multifaceted strategy using a novel low‐cost NTO FTE, CBD‐SnO 2 ‐based PSCs with elevated open‐circuit voltages and energy‐barrier‐free characteristics are fabricated. A champion power conversion efficiency of 20.43% is achieved, and 93.30% of the initial efficiency is retained even after 3 000 h without encapsulation. This integration of a NTO FTE with a SnO 2 ETL paves the way for robust and long‐lasting high‐performance PSCs.