Multi-core@shell double confinement of carbon dots for giant enhancement of thermal Stability: Photoluminescence and lasing up to 1000 K.

• High fluorescence thermal stability carbon dots for photoluminescence and lasing up to 1000 K are realized by multi-core@shell double confinement. • PL intensity of CDs@SiO 2 remains unchanged at 1000 K compared with that at room temperature and retains 92% of the original value after heating at 800 K for 4 h. • High-temperature speckle-free laser imaging is achieved at 800 K by using CDs@SiO 2 lasers as light sources. Low thermal stability has been a common challenge for fluorescent nano-materials in high-power optoelectronic devices or high-temperature environment. In this paper, a double-confined strategy, which is conducted to giant enhancement of thermal stability, is designed for carbon dots (CDs) to form CDs@SiO 2 multi-core@shell structure. This structure can not only prevent CDs from thermal quenching of photoluminescence (PL) up to 1000 K, but also even achieve lasing at such a high temperature without gas protection, indicating the excellent protection of SiO 2 multi-core@shell structure to resist the thermal quenching on one hand, while on the other hand enhance the PL and meanwhile stabilize the luminescence center of CDs. Hence, the CDs@SiO 2 could find a potential application in high-temperature speckle-free laser imaging by using CDs random laser as light source. This research is a major step toward the application of fluorescence materials at high temperature, and meanwhile provides the novel compass to construction of thermally stable fluorescence materials and even laser gain mediums, which could be expected to make a great impact in the area of thermal damage monitoring, manufacturing and aerospace etc. [ABSTRACT FROM AUTHOR]