Construction of Multicolor Phosphorescent Carbon Dots via Multiple Confinement Strategies

Organic room-temperature phosphorescence (RTP) materials are widely used in optoelectronics, biological imaging, and chemical sensing because of their long luminous lifetime and excellent signal-to-noise ratio. Although multicolor RTP systems show important potential for information encryption, spin–orbit coupling (SOC) weakening and exciton quenching caused by molecular motion and environmental factors limit stable triplet exciton generation, thereby reducing the quantum yield and brightness of RTP materials. In this study, we developed a novel carbon dot (CD) to effectively solve these problems using a multiconfinement system, demonstrating excitation-dependent multicolor RTP properties. The RTP of the synthesized CDs varies from green to orange under different excitation wavelengths, with a high photoluminescent quantum yield (54.22%) and RTP brightness (39.53 cd/m²). Through detailed experimental and theoretical studies, we found that these multicolor photoluminescence phenomena arise from the existence of multiple luminescence centers, which form complex network structures through hydrogen, covalent, and ionic bonds, thus effectively stabilizing triplet excitons and enhancing optical properties. In addition, the synthetic material shows application potential in the field of information encryption and anticounterfeiting, achieving dynamic information encryption and multicolor light display functions, improving information security and anticounterfeiting capabilities.