Facile synthesis of thiol-stabilized CdSexTe1−x nanocrystals

CdSexTe1−x nanocrystals (x=0.25, 0.40, 0.50, 0.60 and 0.75) were synthesized using thioglycerol as a stabilizing agent. The composition of the CdSexTe1−x nanocrystals was precisely controlled by tuning the precursor (Se/Te) ratio. The structural, morphological and optical properties of the nanocrystals were analyzed using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), diffused reflectance spectroscopy (DRS) and photoluminescence (PL) measurements. It is found that the Se/Te ratio significantly affects the properties of the resultant CdSexTe1−x nanocrystals. XRD pattern of the CdSexTe1−x nanocrystals revealed cubic, hexagonal and mixed phases depending on the ratio of Se:Te. Surface morphology of the CdSexTe1−x nanocrystals showed nanoclusters of sizes ∼50 nm, with the adjacent cluster interlinking each other. DRS revealed the size dependence band gap energy prevailing in the CdSexTe1−x nanocrystals from 1.52 to 2.66 eV due to the optical bowing effect. PL measurements exhibited band edge emission in the visible spectral region, and are red shifted with increase in Se concentration. The facile route employed in the present work to synthesis the CdSexTe1−x nanocrystals in an aqueous medium is simple and controllable, and the strategy presented will be handy in preparing diverse semiconducting nanocrystals.

Research highlights
► Ternary II–VI semiconductor alloys namely CdSexTe1−x are of crucial importance in the development of novel devices like solar cells, photoconductors, thin films transistors, etc.
► A thorough literature survey reveals that the methods used to prepare CdSexTe1−x nanocrystals utilize complex procedures, sophisticated equipments, or rigid experimental conditions.
► Hence in the present work, an attempt has been made to prepare CdSexTe1−x nanocrystals at relatively low temperatures by hydrothermal synthesis.
► This facile route will be helpful to speed up the preparation of other ternary semiconductor nanoparticles.