Revealing the in-situ growth mechanism of carbon dots confined in ZIF-8 as multicolor fluorescent material with high photothermal stability.

Carbon dots (CDs) based fluorescent materials offer tremendous potential for application in high-definition displays and advanced illumination systems. However, achieving solid-state CDs-based phosphors with robust photothermal stability remains a critical challenge. In this study, multicolor CDs@ZIF-8 phosphors were synthesized by precisely controlling the carbonation degree of CDs under the confinement effect of ZIF-8. Serving as both template and a protective substrate, ZIF-8 enables the in-situ carbonation of the carbon source into CDs embedded within its pores through a solvothermal process. Structural and compositional analyses following HCl etching of the multicolor CDs@ZIF-8 phosphors showed that the in-situ growth of CDs in ZIF-8 pores. The multicolor emission of the CDs is attributed to the quantum size effect. The rigid structure of the ZIF-8 backbone imparts exceptional photothermal stability to the CDs@ZIF-8 phosphors. As a result, the materials exhibit stable fluorescence under continuous laser diode (LD) irradiation for up to 60 min and zero quenching at temperatures as high as 205 °C. These properties are further validated in LD illumination applications. This work provides a novel strategy for the development of high-performance CDs-based phosphors with excellent photothermal stability and offers significant insights into the integration of CDs with porous materials. The findings hold considerable promise for advancing the design and utilization of CDs in solid-state lighting and display technologies.