Cysteine‐Functionalized Ti₃C₂ MXene Quantum Dots as Fluorescent Sensors for the Detection of Ag⁺

Abstract

MXene quantum dots (MQDs), an emerging zero‐dimensional nanomaterial, have garnered significant attention from researchers due to their distinctive physical and chemical properties. In this study, cysteine‐functionalized Ti3C2 MQDs were synthesized using a facile hydrothermal methods, resulting in the functionalized Ti3C2 MQDs exhibiting intense blue fluorescence attributed to size‐dependent effects and surface defects. Furthermore, the cysteine‐functionalized Ti3C2 MQDs exhibit excitation wavelength‐dependent emission behavior and serve as a highly sensitive fluorescent probe for Ag+ detection with an impressive low limit of detection (LOD) of 0.015 μM. Moreover, they demonstrate exceptional sensitivity and selectivity in determining Ag+. This study presents a novel approach for the detection of Ag+ and highlights the immense potential of cysteine‐functionalized Ti3C2 MQDs in environmental applications.