Multisensing Capability of MoSe2 Quantum Dots by Tuning Surface Functional Groups

Several distinct surface-functionalized molybdenum diselenide (MoSe 2 ) quantum dots (QDs) were developed as chemosensors based on the fluorescent probe. The carboxylic-, amine-, and thiol-functionalized MoSe 2 QDs (MoSe 2 /COOH, MoSe 2 /NH 2, and MoSe 2 /SH) were synthesized by tuning their surface with thiol-containing capping agents. These MoSe 2 /COOH and MoSe 2 /NH 2 QD sensors were implemented for the highly selective and sensitive detection of copper ion (Cu 2+ ) and 2,4,6-trinitrophenol (TNP) with a lower detection limit of 4.6 and 45.3 nM, respectively. Similarly, the MoSe 2 /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 Cu 2+, TNP, and MA, based on metal-ion-induced fluorescence turn-on, electron transfer, and energy transfer suppression, respectively. Moreover, these MoSe 2 QD-based chemosensors were successfully utilized in real samples, confirming their propitious application.