Photoluminescent Ti₃C₂ MXene Quantum Dots for Multicolor Cellular Imaging

The preparation of water-soluble, monolayered Ti₃C₂MQDs (MXene QDs) through a facile hydrothermal method was reported. Ti₃C₂MXene was obtained by selectively etching the A layer in the Ti₃ AlC₂ MAX phase with 48% HF acid. The MQDs were prepared through a facile hydrothermal method by cutting the bulk layered Ti₃C₂MXene. Colloidal MQDs with different morphologies could be obtained by changing the reaction temperature. The morphology and structure of the as-synthesized MQDs were studied using transmission electron microscopy (TEM) and atomic force microscopy (AFM). By adjusting the reaction temperatures, MQDs with different atomic concentrations of Ti were obtained. Detailed analysis indicate that the MQDs obtained at 100 °C adopt the pristine structure of MXene, and the MQDs obtained at 120 °C adopt a hybrid structure with C-Ti in the core and TiO₂ at the surface. When the reaction temperature was increased to 150 °C, amorphous carbon dots were obtained.