Dual-Functional Carbon Dot Films: Blue-Light Filtration and Cyan-Light Conversion for Healthier White Light-Emitting Diodes

Abstract

Blue light emitted by commercial white light-emitting diodes (WLEDs) in the 440–470 nm range poses ocular health risks with prolonged exposure. Effective filtration is crucial for health-conscious lighting, but traditional filters often cause color distortion by completely removing blue emission. In this study, we address this challenge by synthesizing carbon dots (CDs) with strong absorption at 460 nm and bright cyan emission at 485 nm, featuring a photoluminescence quantum yield of 65% and a narrow full width at half-maximum of 30 nm. When embedded in a poly(vinyl alcohol) (PVA) matrix, the CDs@PVA films effectively filter UV-to-blue light, reducing the blue-light ratio from 27.2% to 2.7%. At the same time, the cyan emission preserves the white light’s spectral composition, achieving a color rendering index of 83 ± 5. This dual functionality demonstrates the potential of CDs to enable safer WLEDs that improve both ocular health and lighting quality.