Surface polymerization of melamine resin on a perovskite: enhancing the efficiency and stability of solar cells

Abstract

We report a melamine formaldehyde resin (MF) interlayer which is formed via the heat-induced polymerization of hexakis(methoxymethyl)melamine on the surface of organic–inorganic hybrid perovskites. The MF interlayer effectively reduces the defect density of the perovskite, enhances the excited state and charge transport performance, and significantly mitigates perovskite film decomposition and morphology deterioration in the hole transport layer at elevated temperatures. By incorporating the MF interlayer, we successfully fabricate 85 °C long-term stable solar cells, utilizing light absorption layers based on a triple-cation perovskite and FAPbI₃ perovskite, achieving initial average efficiencies of 22.2% and 23.7%, respectively. Furthermore, the solar cell employing the MF-modified triple cation perovskite exhibits exceptional operational stability at 65 °C under full sunlight irradiation.