One-Step Microwave Solid-State Synthesis of N, S Co-Doped Carbon Dots and Their Multifunctional Applications.

Nitrogen and sulfur co-doped yellow-green fluorescent carbon dots (N,SCDs) were synthesized using thiourea and 5-sulfo salicylic acid as raw materials through a one-step microwave solid-phase method. A series of characterizations, including transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FT-IR), UV-Vis spectrum, and fluorescent spectrum, were conducted, revealing that N,SCDs are carbon dots with an average size of approximately 5.65 nm.