Synthesis and optical properties of composition-tunable and water-soluble ZnxCd1−xTe alloyed nanocrystals

ZnxCd1−xTe alloyed nanocrystals with different compositions (x=0, 0.3, 0.5, 0.7) have been synthesized in aqueous solution with thioglycolic acid (TGA) as stabilizer. The samples have been characterized by X-ray diffraction pattern (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), and X-ray photoelectron spectra (XPS). The optical properties of the alloyed nanocrystals have been investigated by UV–vis absorption and photoluminescence (PL) spectroscopy. Composition-dependent absorption and PL spectra are observed for ZnxCd1−xTe alloyed nanocrystals with increasing Zn content. The highest PL quantum yield (QY) of obtained ZnxCd1−xTe alloyed nanocrystals is 20.2%. The effect of refluxing time and synthesis temperature on the optical properties of the alloyed nanocrystals has also been investigated. The PL peak position of ZnxCd1−xTe alloyed nanocrystals does not show significant shift under different excitation wavelengths.