Interfacial Interactions in CdTe/MX (M = Zn, Cd, Sb, Bi; X = Te, Se, S, O) Nanoparticles: Implications for Glutathione Fluorescence Detection

In this work, a series of in situ-grown CdTe/MX (M = Zn, Cd, Sb, Bi; X = Te, Se, S, and O) nanoparticles were applied to monitor glutathione (γ-l-glutamyl-l-cysteinyl-glycine, GSH) via fluorescence spectroscopy based on its unique physicochemical and photoelectric properties. Special attention was paid to the effect of the energy level alignment on the fluorescence response of GSH at the CdTe/MX interface. In particular, the signals produced by the −SH group of GSH exhibited fluorescence enhancement and quenching. Both signal changes were due to the conduction and valence band alignments promoted by the CdTe/MX interface. Besides fluorescence response aspects, the interfacial interaction at the CdTe/MX interface was also shown to be crucial due to its role in charge transportation. Finally, the fluorescent detector based on the CdTe/CdO nanoparticles demonstrated excellent sensing performance with a detection limit up to 1 μM in the wide linear range, as well as acceptable stability. Therefore, this work provides insights into the rational combination of MX with CdTe and highlights the overlooked effect of the interfacial interaction on GSH detection.