Rapid microwave synthesis of highly optically and thermally stable boron-doped carbon dots fluorescent materials

Abstract Carbon dots (CDs), with the advantages of low toxicity, easy functionalization, and excellent optical properties, have shown great application potential as photo-conversion phosphors. However, the severe demands of laser diodes (LD) on the stability of phosphors limit the application of CDs in laser lighting. Herein, CDs doped with boron were synthesized through rapid microwave heating, exhibiting exceptional stability both optically and thermally. Experimental results demonstrate that the microwave synthesis process of CDs leads to the formation of incompletely carbonized small molecular products such as α-quinoline ketone and 5-(4-methoxyphenyl)-1H-tetrazole grafted onto the surface of CDs, and the highly stable α-quinoline ketone contributes to improving the thermal stability of CDs. Additionally, doping with element B can alter the surface properties of CDs, thereby enhancing their fluorescence intensity. Furthermore, a fluorescent film was fabricated by dispersing yellow-green emitting B-doped CDs in KH-792. When this film was combined with a 450 nm LD, this resulted in the creation of a laser diode device that emits a yellowish-white light.