Titanium carbide (Ti3C2Tx) MXene: A novel precursor to amphiphilic carbide-derived graphene quantum dots for fluorescent ink, light-emitting composite and bioimaging

Synthesis of fluorescent carbide-derived carbons (CDCs) remains a big challenge for material scientists. Herein, we report an unprecedented method for the synthesis of amphiphilic carbide-derived graphene quantum dots (GQDs) from layered Ti3C2Tx MXene using solvothermal treatment of Ti3C2Tx MXene in dimethylformamide (DMF). Our findings indicate that DMF can simultaneously act as reaction media and nitrogen-doping agent for the formation of highly fluorescent carbide-derived GQDs. The resulted GQDs with uniform size distribution exhibit excellent dispersibility in both hydrophilic solvents (e.g., water, DMF, and ethanol) and in hydrophobic solvents (e.g., chloroform and toluene). With their superior properties of bright and tunable photoluminescence, low cytotoxicity, good photostability and chemical inertness, the carbide-derived GQDs are promising for applications in fluorescent ink, light-emitting composites and cellular imaging as demonstrated in this paper. This work opens a new route towards the large-scale synthesis of high-quality GQDs, paving the way for their versatile applications.