Luminescence dynamics of Te doped CdS quantum dots at different doping levels.

We have examined steady-state and time-resolved luminescence properties of CdS:Te quantum dots (QDs). The transient emission spectra have a red shift along the emission process. Using singular value decomposition and multiexponential decay analysis, the luminescence is found to originate from two distinct and parallel channels: band-edge excitonic emission and trapping state emission. With increasing amount of Te, the emission peaks of the QDs show an obvious red shift. Our experimental results suggest that CdS:Te quantum dots have tunable emission spectra and luminescence lifetimes which may have applications in chemical sensing, high throughput screening and other biotechnological applications.