Abstract
Organic photovoltaics (OPVs) show promise as a sustainable energy solution but lack long-term stability under real-world operating conditions. Exposure to UV light and moisture can cause performance degradation over time. Protective coatings that isolate devices from these factors without compromising OPV advantages like flexibility and light weight are helpful to enhance the device lifetime. This work develops down-converting fluorophore-embedded composite coatings to address the device stability. The coatings are designed to convert harmful UV photons into visible light that can be harvested by OPVs. The coating formulation was optimized to maximize downconversion while preventing fluorescence quenching. When the developed coatings applied to PM6:Y6 solar cells, the operational lifetime of devices are significantly extended. The tested device can retain 95% of its initial efficiency more than 600 hours under the maximum power point condition.