Aqueous Phase Synthesis of ZnTe Quantum Dots Using Sodium Tellurite

ZnTe Quantum dots (QDs) were successfully synthesized via co-precipitation method in an aqueous medium by using sodium tellurite (Na2TeO3) as the tellurium precursor, for the first time. Using sodium tellurite caused avoiding the complicate processes associated with the preparation of NaHTe and H2Te precursor materials and facilitated the synthesis process. Phase and microstructure of the obtained QDs were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) methods, and their optical properties were studied by UV-Vis absorption and photoluminescence spectroscopy measurements. XRD analyses revealed formation of single phase wurtzite ZnTe nanocrystals. The average nanocrystallite size was estimated by the Williamson–Hall method, came out to be ~ 2 nm. Optical band gap of the produced QDs was determined through fitting the measured optical absorption spectra, which confirmed quantum confinement effects. The average size of nanocrystals was calculated based on the optical data, using the Brus equation, to be 2.1 nm, which is close to the Williamson-Hall calculations. TEM micrographs indicated that ZnTe QDs with rather spherical shape and uniform morphology are obtained.