A self-quenching-resistant carbon dots powder with tunable solid-state fluorescence and their applications in light-emitting diodes and fingerprints detection

In this report, a novel type of carbon dots (CDs) were prepared via a simple MW-assisted method by using citric acid and piperazine as precursors. The CDs can be obtained in large-scale and emit bright solid-state fluorescence (SSF) with different colors. Then the synthetic CDs were fully characterized with PL, UV, XPS, TEM, and FTIR and the relationship between the mass ratio of precursors and physicochemical property of the CDs was also investigated detailedly. The results showed that these CDs prepared at different mass ratios have different element content and functional group content. More importantly, the mass ratio of the precursors not only has a great influence on their particle sizes, but also can affect their PL properties. With the decreased of the mass ratio, their particle size decreased gradually and their emission wavelength gradually red-shift. This interesting finding may be helpful for fabricating CDs with controllable particle size and tunable light-emitting colors. Based on their excellent SSF property, these CDs were successfully used to fabricate light-emitting diodes (LEDs) and detect latent fingerprints (LFPs). In conclusion, the research may offer a valuable reference for obtaining CDs with SSF and developing LEDs phosphors and LFPs detection reagent.