The Photoelectric Properties And Electrochemical Performance Of Two Typical Zinc-based Nanomaterials

Nanomaterials have been widely investigated in optical, electrical and energy field because they have many novel physical and chemical properties different from bulk materials. In this paper, the optical and electrical properties of ZnSxSe1-x nanostructures, the electrochemical properties of ZnCo2O4/Ni(OH)2 nanostructures and their preparation have been studied in detail.First, ZnSxSe1-x(0≤x≤1) alloy nanostructures were prepared in this paper. The studies about ZnSx Se1-x alloy nanostructures demonstrate that the ZnSxSe1-x alloys have a wurtzite-type hexagonal crystal structure measured by X-ray diffraction. With the increase of the S content, their reflectance and photoluminescence spectra blue-shift continuously, further indicating the formation of the alloyed nanostructures. Raman spectra investigations demonstrate typical two-mode behavior. Moreover, the current versus voltage curve and photoresponse of the photodetectors were also tested. The results reveal that the photoconduction of the ZnSxSe1-x nanostructure is sensitive to the UV illumination. Furthermore, the mechanism of photoconductivity is proposed, and the reasons for slow photoresponse are suggested. All of these indicate that the ZnSxSe1-x alloy nanostructures have a broad application prospect in developing the ultraviolet radiation light sensors and photoelectrical switch devices.Second, the ZnCo2O4/Ni(OH)2 nanowires composite electrodes were synthesized on Ni foam using hydrothermal method and electrodeposition. The studies about ZnCo2O4/Ni(OH)2 composite electrodes demonstrate that the ZnCo2O4 nanowires grown on Ni foam not only can served as backbones to improve the electrical conductivity of redox active Ni(OH)2 electrode materials, but also can enhance the specific surface areas of electrode materials, and solidify the Ni(OH)2 electrode materials onto Ni foam as current collector. Ni(OH)2 nanosheets were then electrodeposited onto the ZnCo2O4 nanowires. The electrochemical performances of the hierarchical ZnCo2O4/Ni(OH)2 nanostructures were measured. Their specific capacitance is 2826 F/g at a current density of 2 mA/cm2, the good rate capability is 71.4% from 2 to 20 mA/cm2, the cycling stability is 72% after 2000 cycles at a high current density of 10 mA/cm2, and the specific energy density is 166.7 Wh/kg at a current density of 2 mA/cm2 in a two-electrode system. These results illustrate that the hierarchical ZnCo2O4/Ni(OH)2 composite electrodes are very promising in high-performance supercapacitor application.