| With the rapid development of economy, science, technology and social production isimproved fast, the higher requirement for energy saving and environmental protection is concerned,which become the focus in the world gradually. Especially in recent decades, as the rapiddevelopment of automobile industry, transportation, construction industry and other fields, a largenumber of transparent solar thermal isolation materials and devices with economic, high efficiency,energy saving, which are used to reduce the surface environment and operation temperature ofapparatus under the strong light are needed urgently so as to save energy effectively and protect theenvironment feasibly.The common glass has no selectivity to the sunlight. Though they have a high transmittanceof the visible light, the area of the near-infrared light (which contain the main energy in the sun) ofheat is passed greatly. It can cause a high indoor temperature, which significantly increases theburden of cooling equipment (such as air condition, air cooler), so the energy is used up and wastedas well. According to this phenomenon, it is important to find the solar thermal shielding devicethat can reduce the indoor temperature, while maintaining enough brightness and it has highapplication and research value.The nano semiconductor metal oxide, sulfides compounds with its unique physical andchemical properties show many advantages in solar thermal shielding materials, and hope to bewidely used. The paper is based on the current research progress of nanomaterials and in this paper,the main properties and the preparation methods were summarized. The work will be done asfollows:1) the chemical coprecipitation and ultrasonic atomization coprecipitation preparationtechnology are discussed;2) the calcination process, size and crystal phase morphology of nano-powders are studied;3) concentration on the optical properties of nano tungsten oxide, coppersulfide nanoparticles and the dual-metal sulfides were studied.In chapter one, the research and developing trend of thermal shielding materials andnanoparticles were introduced in details. The preparation technology and characterization ofnanometer compound is studied. The characteristics and application of semiconductornanoparticles were analysed, and also the related theory in this paper.In chapter two, the nano-powder of tungstate was firstly prepared by chemical precipitation process with ammonium tungstate and nitric acid as raw materials at room temperature and normalatmospheric pressure. The influence of reduced in different temperature on chemical compositionwas studied. The morphology of before and after reduction was analysed. The absorption andtransmittance of tungstate oxide from200nm to2500nm wavelength indicate that it has a highabsorbance in1400~2500nm wave band for near infrared light and a high transmittance for visiblelight.In chapter three, the nano copper sulfide was prepared by ultrasonic atomization withCu(NO3)2and Na2S solutions as raw materials. The influences of ratio of Cu and S, and heatedtemperature on chemical composition of copper sulfide were studied. The morphological image ofthe copper sulfide was analysed. The experiments indicate that the copper sulfides were of highabsorbance for near infrared light, which were attributed to the electronic transitions in the energybands. They also had high transmittance for visible light. But the transmittance declined slightly asCu2S approached to CuS.In chapter four, several dual-metal sulfides were prepared by ultrasonic atomization and co-precipitation with Fe(NO3)3, Al(NO3)3, Ba(NO3)2, Gd2O3, Cu(NO3)2and Na2S as raw materials.The morphology and chemical composition of dual-metal sulfides was analysed. The absorptionand transmittance of nanoparticles from ultraviolet to near infrared wavelength were recorded. Theresults indicate that the dual-metal sulfides are of high absorbance for near infrared light, whilehigh transmittance for visible light. |
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