One-pot hydrothermal synthesis of fluorescent carbon quantum dots with tunable emission color for application in electroluminescence detection of dopamine

Existing carbon quantum dot (CQD) synthesis approaches for the detection of dopamine (DA) require additional processes for separating quantum dots, which makes them complex and decreases the yield. Therefore, a facile CQD synthesis approach without complicated processing steps or reaction conditions is required. In this study, CQDs were synthesized via an environment-friendly one-step hydrothermal approach using glucose and potassium phosphate as the starting materials. The fluorescent colors emitted by the synthesized CQDs were dependent on the amount of potassium phosphate used. The mechanism of CQDs emitting different colors of fluorescence was theoretically speculated by computational simulation. The electronic and optical properties of CQDs models with different sizes are studied by density functional theory (DFT). An electroluminescence (ECL) sensing platform based on the fluorescent CQDs was developed for the detection of DA. Under optimal conditions, the ECL intensity of the CQDs decreased linearly when the DA concentration was controlled within the range of 10−8–10−4 M. The results showed that the ECL sensing platform can be successfully applied for the determination of DA content within a certain concentration range, with a detection limit of 62 nM.