Multisensing Capability of MoSe₂ Quantum Dots by Tuning Surface Functional Groups

Several distinct surface-functionalized molybdenum diselenide (MoSe2) quantum dots (QDs) were developed as chemosensors based on the fluorescent probe. The carboxylic-, amine-, and thiol-functionalized MoSe2 QDs (MoSe2/COOH, MoSe2/NH2, and MoSe2/SH) were synthesized by tuning their surface with thiol-containing capping agents. These MoSe2/COOH and MoSe2/NH2 QD sensors were implemented for the highly selective and sensitive detection of copper ion (Cu2+) and 2,4,6-trinitrophenol (TNP) with a lower detection limit of 4.6 and 45.3 nM, respectively. Similarly, the MoSe2/SH QDs while coupled with gold nanoparticles showed excellent selectivity toward melamine (MA) with a lower detection limit of 27.7 nM. It is surprising to find that each functionalized QD exhibits a distinct sensing mechanism in the detection of Cu2+, TNP, and MA, based on metal-ion-induced fluorescence turn-on, electron transfer, and energy transfer suppression, respectively. Moreover, these MoSe2 QD-based chemosensors were successfully utilized in real samples, confirming their propitious application.