Efficient and Moisture Resistant Wide-Bandgap Perovskite Solar Cells with Phosphinate-Based Iodine Defect Passivation

Abstract

Commercialization of perovskite-based tandem solar cells requires preparing wide-bandgap (WBG) perovskites in an ambient atmosphere environment. Here, producing high-performance and stable WBG perovskite solar cells (PSCs) is demonstrated with blade coating in ambient air (≈60% relative humidity, RH) using sodium benzene phosphinate (SBP) as an additive modulator in the perovskite precursor. SBP can effectively suppress I⁻ oxidation in high humidity ambient air, inhibit ion migration, and thus inhibit phase separation; it also modulates the crystallization of perovskite grains, passivates surface defects, and improves the hydrophobicity of perovskite film. The devices incorporating SBP achieved a power conversion efficiency (PCE) of up to 22.1%, which is the state-of-the-art result for the WBG PSCs (≥1.68 eV) fabricated in ambient air with the blade coating method. In addition, the same protocol produces a PCE of 20.1% for a larger area cell (1.05 cm²), and a PCE of over 19.5% for unit cells on a 100cm² substrate. The unencapsulated devices exhibit excellent stability, i.e., 90.3% efficiency retention after 2000 h with air exposure (≈60% RH) and 86.3% efficiency retention after 1000 h at 85 °C in an argon atmosphere. This SBP-based material modulation for the preparation of WBG PSCs provides a new opportunity for manufacturing perovskite photovoltaics.