Dual-Amino Nitrobenzene Functionalization Enables Graphene Quantum Dots for Selective UV and High-Energy Blue-Light Filtering

Abstract

High-quality optical filters that selectively attenuate harmful ultraviolet (UV) and high-energy blue light (HEBL, 400–450 nm), while maintaining high visible transparency, are critically important for health-conscious lighting. However, achieving such precise spectral selectivity remains challenging, as conventional blue-light filters often cause color distortion by fully eliminating blue emission. Herein, we report a molecular functionalization strategy to finely regulate the optical absorption of graphene quantum dots (GQDs) through covalent grafting of aminonitrobenzene derivatives. By systematically varying substituent configuration and donor density, the interfacial donor-acceptor coupling strength between the molecular moieties and the GQD π-conjugated framework is effectively modulated. Among the designed systems, DNP-GQDs bearing dual-amino nitrobenzene groups exhibit markedly enhanced and selective absorption in the UV and HEBL regions. Owing to their excellent water solubility, DNP-GQDs are embedded in poly(vinyl alcohol) (PVA) to fabricate transparent DNP-GQDs/PVA films. An optimized film containing 0.5 wt% DNP-GQDs achieves nearly complete shielding of UV and HEBL, while retaining high visible-light (> 540 nm) transmittance exceeding 80%. Importantly, under white light-emitting diode (WLED) illumination, the films enable controlled spectral reshaping, shifting chromaticity coordinates from (0.3066, 0.3247) to (0.3653, 0.4070), corresponding to a transition from cool to warm white light with acceptable color rendering. This work establishes a clear molecular structure-electronic interaction-optical response relationship and provides a general strategy for designing spectrally selective nanocarbon-based optical filters for advanced lighting applications.