Induction Synthesis of Functionalized Graphene Quantum Dots and Their Aggregation-Induced Emission Properties to Glucose in Aqueous Solutions

This study adopts an induction heating technique (i.e., infrared carbonization (IRC)) to synthesize functionalized graphene quantum dots (GQDs) with different dopants, including N, B, and S atoms. The as-synthesized GQDs were employed as biomarkers in plants (lettuce and Chinese cabbage) and as sensing probes for detecting glucose in aqueous solutions. The IRC method is highly adaptable for in situ doping of various atoms within the graphitic framework of GQDs. Remarkably, adsorption of glucose on as-prepared GQDs enhances the photoluminescent (PL) efficiency (up to ∼7.3 fold) from the GQD suspensions under UV illumination. The GQD–(glucose)x intermediates exhibit enhanced PL performance through an aggregation-induced emission (AIE) mechanism, particularly when hydrophilic GQDs accumulate. The AIE effect becomes more pronounced as GQD aggregation increases, resulting in progressively enhanced fluorescence in the presence of glucose. This organized clustering confirms that the formation of GQD–(glucose)x intermediates plays a crucial role in enhancing photoluminescence through the AIE mechanism. The resultant AIE-enhanced GQD clusters demonstrate exceptional luminous characteristics, providing them desirable for applications in sophisticated bioimaging and sensing technologies.