Preparation Of ZnO Nanowires And Characterization Of Infrared Emission Properties

This paper adopts a method combined the theoretical and experimental research, to explore the low infrared emission mechanism and the law of semiconductor coatings of ZnO by means of its conductive properties, the relationship between particle scattering properties and the infrared emissivity.In theoretical research, based on the first principle of density functional theory (DFT), the electronic structures of intrinsic bulk ZnO system Al doped system, the system of Sn doping, Sb doping system four different system were simulated and calculated and the theory of the optical properties were researched. Comparing their energy band diagram, state density diagram, layout, atomic imaginary part dielectric function and the infrared reflectivity figure. The results show that the infrared reflectivity increased with the increase of Al, Sn doping concentration, which be beneficial to lower the infrared emissivity of ZnO nanowires. However, with the improvement of Sb doping concentration, the infrared reflectivity has decreased and some increased. Therefore, we cannot depend on the Sb doping of high concentration to improve ZnO nanowires reflectivity, and should reasonable design experiment according to the results of this part of the theory study. All of these will provide a theoretical guidance for the further design and preparation of high performance low infrared emissivity materials.In the experiment, using Zn(NO3)2·6H2O as the source material, and KOH as themineralizer, ZnO nano-powder materials were prepared by hydrothermal method, and based on the orthogonal design theory to optimize the technological parameters of preparation of ZnO Nano-powder materials. The composition of samples, microstructure, morphology, infrared emission rate were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS) and infrared emissivity measuring instrμment and so on. The results show that:different morphology of ZnO nano-powders with different process parameters have the different infrared emissivity, the lowest infrared emissivity is0.74. By analyzing the results of the products characterization, emission rate of ZnO nano-powders firstly decreased and then increased with the increase of the concentration [Zn2+], and firstly increased and then decreased with the increase of [Zn2+]/[OH-], T hydrothermal temperature, hydrothermal time T. From this analysis, with Indicators of low infrared emissivity, the level of the corresponding optimization is [Zn2+]=0.05mol/L,[Zn2+]/[OH-]=10, T=140℃, T=18h, respectively.Based on the optimized technological parameters, Sb、Al、Sn doped ZnO nano-powder materials which used SbCl3、Al(NO3)3·9H2O、SnCl2·2H2O as dopant were prepared. Then, analysis about the influence of Sb、Al、Sn doping concentration on the infrared emitting rate were carried out. The results show that the increase doping concentration effectively reduced the infrared emitting rate. This article analyzed the control mechanism of the infrared emitting rate from the microscopic.