Controlled Synthesis, Growth Process And Property Investigation Of Cds Nanomaterials

Cadmium sulfide (CdS) is a typical II-VI group semiconductor material with a wide band gap of2.42eV at room temperature. Because of its excellent optical properties, it is widely applied in biological sensors, photocatalysis, solar cells, light-emitting diodes and other optical devices. It is well known that the properties of nanomaterials depend closely on their size and morphology, so the controlled synthesis of nanomaterials is important for controlling their properties and extending their application fields. And exploring the processing technique, monitoring the detailed information during the growth process, explaining the growth mechanism of nanomaterials with different morphology are the key elements to achieve the controlled synthesis of nanomaterials. In this paper, CdS nanomaterials were chosen as the research object. A variety of CdS nanostructures have been successfully fabricated in three systems at room temperature by altering the experimental parameters. And the growth processes, mechanisms and properties of these CdS nanomaterials have been investigated.In situ microcalorimetry was used to investigate the energy evolution during CdS nanocrystal growth process. The CdS nanospheres and CdS hollow nanospheres were synthesized in the glycol-water system at room temperature. The energy changes of the growth processes of CdS nanospheres and CdS hollow nanospheres were measured by a microcalorimeter, respectively. On the basis of the microcalorimetric curves, the growth mechanisms of CdS nanospheres and CdS hollow nanospheres have been proposed. At the same time, the CdS nanospheres and CdS hollow nanospheres were also characterized by X-ray diffraction, scanning electron microscope and photoluminescence spectra. The correctness of microcalorimetric analysis about the CdS nanocrystal growth can be proved by the SEM images and PL spectra. Moreover, the rate constant and the activation Gibbs energy of CdS nanospheres, the standard molar formation enthalpy of the CdS hollow nanospheres have been obtained.The CdS nanotubes and olive-like CdS nanomaterials were prepared by the microemulsion solutions of Triton X-100/n-octanol/cyclohexane/water system with different experimental parameters. The growth processes of the two different morphologies of CdS nanostructures were researched by microcalorimetry, and the growth mechanisms of them were also presented.In the light of the synthesis conditions of olive-like CdS nanomaterials, the effects of reagent concentration and the molar ratio of water and surfactant on the morphology were discussed. In addition, the optical properties of CdS nanotubes were investigated by UV-Vis and PL spectra. Then, cadmium acetate and sodium sulfide were chosen as starting reagents, and the relatively uniform CdS nanocubes with sides of100nm were successfully synthesized in the Triton X-100microemulsion system at room temperature.The CdS nanocuboids with grooves were synthesized in the Tween-80/n-pentanol/cyclohexane/water microemulsion system at room temperature and characterized by TEM. The morphology of this product was extremely special, and some novel properties may be discovered. Therefore, further research is needed to explore the growth mechanism and properties of this product.This paper focused on exploring the facile liquid-phase synthesis routes of CdS nanomaterials. And the microcalorimetry was used to investigate the growth processes of CdS nanomaterials for the first time. This research can provide important reference value for the controllable synthesis of the CdS nanomaterials.