Microwave Assisted Synthesis of N,S-Doped Carbon Quantum Dots as a Fluorescent Sensor for Silver(I) Ions

Using–cyclodextrin, melamine, and thiourea, a simple and affordable method based on microwave treatment was established to generate nitrogen and sulphur co-doped carbon quantum dots (N,S-CQDs). Upon UV exposure, they displayed intense blue fluorescence with a 24% quantum yield (QY). Several characterization approaches were used to examine the optical, structural, and morphological characteristics of the N,S-CQDs. The average diameter of the spherical particles was 4 nm. A fluorescence sensor for Ag(I) ions with a limit of detection (LOD) of 45 nM and a linear detection range of 0–20 M was successfully built using N,S-CQDs. The quenching procedure follows a static quenching mechanism.