Preparation and characterization of highly luminescent water-soluble CdTe quantum dots as optical temperature probes

Highly luminescent water-soluble CdTe quantum dots were synthesized with an electrogenerated precursor. The size, morphology, optical properties as well as fluorescence stability were characterized by transmission electron microscope, high-resolution transmission electron microscope, powder X-ray diffraction, UV-vis-NIR spectrophotometer, and fluorescence spectrophotometer. The results show that the CdTe QDs with diameter ranging from 2.0 nm to 3.5 nm have good crystallizability, high quantum yield and favorable fluorescence stability. Moreover, the CdTe QDs demonstrate temperature-dependent reversible PL intensity variations at moderate temperatures above room temperature. It is also found that the QDs with different sizes possess different sensitivity to the temperature. All the studies indicate that the CdTe QDs are expected to be promising candidates for a variety of biological and biomedical applications.