| 초록 |
Sulfur-Nitrogen co-doped graphene quantum dots (S,N-GQD) are synthesized through one-pot carbonization processing of citric acid under the sulfuric acid and dimethylformamide (DMF) condition at low temperature (＜160°C). Sulfuric acid as a sulfur dopant catalyzes the dehydration of citric acid. DMF is a nitrogen source and also serves as a quenching solvent to retard the growth of graphene quantum dots to graphene oxide. Incorporated sulfur and nitrogen induce new surface states, which could facilitate more radiative recombination of exciton. In conclusion, the prepared S,N-GQDs exhibit an excellent fluorescence quantum yield (61%), approximately 7 times higher than that of pristine GQDs (9%), with long photoluminescence life time (τ =7.6 ns). Furthermore, this simple and large-scale synthesis of highly fluorescent GQD gives promise for applications in biosensors and optoelectronic devices. |
