Cascade mechanism of fluorescence enhancement in a ZnO–graphene quantum dot/epoxy-acrylate hybrid nanocomposite

Subject of study . This study investigates the optical properties of a composite based on an epoxy-acrylate oligomer modified with ZnO nanoparticles (NPs). This study also considers the development of multifunctional polymer coatings for solar cells capable of converting ultraviolet (UV) radiation into visible light. Aim of study. The aim of this study is to develop a model establishing a cascade energy-transfer mechanism to enhance fluorescence. Method. The optical properties were investigated by absorption spectroscopy and fluorimetry using a Hitachi U-3410 spectrophotometer and a Hitachi F-4010 spectrofluorimeter. Main results . A cascade mechanism for fluorescence enhancement was experimentally established and theoretically substantiated. ZnO NPs acted as nanoresonators, and they absorbed UV radiation and underwent recombination through an exciton–polariton channel with subsequent re-emission. The re-emitted photons were effectively absorbed by graphene quantum dots (GQDs), leading to radiative transitions in the visible spectral range (410–480 nm). A cascade energy-transfer mechanism from the ZnO nanoresonators to the GQDs was established and substantiated for the first time. Practical significance. The obtained results enable the development of coatings that enhance the efficiency of solar cells.