Towards efficient dual-emissive carbon dots through sulfur and nitrogen co-doped

Herein, unique S and N co-doped carbon dots (S,N-C-dots) were synthesized via a one-pot hydrothermal method. The S,N-C-dots not only possess a relatively high photoluminescence (PL) quantum yield (QY) (43%), but also present unique optical properties with dual-emission (blue and yellow) and excitation-independent characteristics. It is extremely rare for bare carbon dots (C-dots) to have dual-emission under single excitation wavelength. Herein, we achieved a series of solid-state lighting materials, such as silica-encapsulated C-dots (silica/C-dots), light conversion films (LCFs), and white-light-emitting diodes (WLEDs), using S,N-C-dots as a doping fluorophore. Moreover, we conducted some comparative experiments to prove that the unique properties of the S,N-C-dots were ascribed to the co-doping effects of S and N atoms. The yellow emission originates from the intrinsic state emission and the blue emission originates from the surface energy trap emission. This study presents a facile preparation of highly efficient dual-emissive S,N-C-dots and provides a new strategy to develop various solid-state lighting materials.