High-Temperature Phosphorescence of Carbon Dots by a Synergistic Locking Strategy

Phosphorescent materials have potential applications in anticounterfeiting and optoelectronics, but their luminescence is generally quenched at elevated temperatures. Herein, a synergistic locking strategy has been developed to achieve high-temperature phosphorescence (HTP) of carbon dot (CD) composites. Impressively, the CD composites retain over 90% and 75% of their phosphorescence intensity at temperatures up to 110 and 170 °C, respectively. Even at temperatures higher than 170 °C, the phosphorescence persists for 5 s, demonstrating remarkable stabilization of triplet excitons. Experimental and theoretical results revealed that this outstanding thermal resistance stems from the synergistic locking effect of interlayer covalent bridges and multiple hydrogen bonding at the interface. Furthermore, by adjusting the degree of graphitization, multicolor HTP ranging from blue to red has been achieved for the CD composites. This work not only provides a facile and versatile way to construct multicolor CD-based HTP materials but also expands their potential applications in heat-resistant display at high-temperature environments.