Tunable Near-White Light Emission From a Single-Molecule via Strategic Utilization of Aldehyde-Gemdiol Intrinsic Equilibrium

White-light emitting organic materials have garnered significant attention due to their potential applications in lighting and display technologies. Compared to systems that emit distinct colors by combining multiple molecules, single-molecule white-light emission systems offer notable advantages, such as simple preparation, good repeatability and stability. In this study, a novel fluorescent molecule (BTP-CHO) was developed. For the first time, a single-molecule near-white light emission system by exploiting the internal equilibrium of aldehyde-gemdiol in water of BTP-CHO was constructed. BTP-CHO exists predominantly as the aldehyde form in DMSO and shows green fluorescence; while BTP-CHO shows blue fluorescence because of the internal equilibrium of aldehyde-gemdiol in water. Polychromatic photoluminescence could be achieved by fine-tuning various parameters, including excitation wavelength and solvent ratio. Additionally, we synthesized three derivatives of BTP-CHO for further investigating the universality of this strategy and the results indicate that the strategy has good universality. Finally, BTP-CHO was successfully applied in the development of information encryption and near-white light hydrogels. This work provides new insights into the design of organic single-molecule white-light emitters and broadens the scope of research on aldehyde-gemdiol intrinsic equilibrium about white-light emitting.