Melatonin treatment as an anti-aging therapy for UV-related degradation of perovskite solar cells

Abstract

Perovskite solar cells exhibit immense potential for practical use due to their high power conversion efficiency (PCE) and low fabrication cost. However, UV light is an unavoidable threat to long-term stability as it promotes undesirable chemical reactions within the cells. Herein, we introduce N-acetyl-5-methoxy-tryptamine (melatonin), a natural product with antioxidative properties, for the UV protection of perovskite, attributable to its ability to absorb UV light and scavenge radicals. Additionally, the defects in perovskite are effectively passivated due to interactions between perovskite and melatonin. Consequently, the photovoltaic performance is enhanced due to reduced defect density in the perovskite and the improved charge transport from the perovskite layer to the charge transport layer. Furthermore, the devices fabricated using this strategy demonstrate an outstanding storage stability, retaining 85% of the initial PCE after 2225 hours of storage in air (unencapsulated, 20–30 °C, RH ∼30%), and UV endurance, sustaining 70.86% of the original PCE after UV illumination for 617 hours in air.