Bio-Inspired Engineering of Anti-Aging Natural Cyanidin toward Air-Stable Tin-Based Perovskite Solar Cells

Highly chemically stable perovskite films play a vital role in the advancement of tin-based perovskite solar cells (PSCs). In this work, we present the preparation of air-stable tin-based PSCs by adding natural molecular cyanidin as an antioxidant additive to the perovskite precursor solution inspired by biological anti-aging research. The moderate reduction of the o-phenol hydroxyl group inhibited the valence conversion of Sn2+ ions to Sn4+ ions and greatly enhanced the stability of the perovskite films in terms of oxidation. Meanwhile, the coordination of −C═O and −OH with Sn2+ promoted the formation of uniform and substable precursors with large cluster particle sizes, reducing the defect state and stabilizing the perovskite lattice structure. The power conversion efficiency (PCE) of the champion-modified devices was increased from 10.32 to 12.97%. The unencapsulated devices retained their initial efficiency of ∼80% after 600 h of exposure to air conditions under the relative humidity around 30%. We present a simplified and feasible strategy in this study for the preparation of high-quality, low-defect tin-based perovskite films.