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

초록

Perovskite solar cells (PSCs) incorporating chemical-bath-deposited (CBD) SnO2 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 SnO2 (NTO) FTEs tailored to integrate with CBD-SnO2-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 Omega/square, an optical transmittance of 86.17%, a smooth surface morphology (1.2 nm), and mechanical flexibility is obtained. Furthermore, doping N in SnO2 imparts thermal and chemical stability superior to those of conventional Sn-doped In2O3 (ITO) electrodes. Additionally, a well-matched energy band of NTO with a SnO2 electron transport layer (ETL) and homogeneous interfaces is a critical advantage. By implementing this multifaceted strategy using a novel low-cost NTO FTE, CBD-SnO2-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 SnO2 ETL paves the way for robust and long-lasting high-performance PSCs.

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