Preparation And Research Of Protective Films For Space Solar Cells

Presently, even in the future, the study and application of solar energy is an important direction of using energy. In development and use of solar energy, people developed the solar cell, and made solar power into electrical energy or the other energy. However, the mechanical strength of solar cell is not very good, and the solar cell is easily damaged. Therefore, protective medium is needed. At present, irradiation resistant glasses are used to serve as physical protection for the space of solar battery. In order to reduce the weight of solar cells and the broken rate of protective mediums, protective films for space solar cells which deposited by Sol-Gel are studied in the paper.The dissertation consists of four parts:1. Optimization of Sol-gel processAt first, the silica antireflective films were prepared by the sol-gal method with TEOS as the precursor, ethanol as the solvent and hydrochloric acid as the catalyst. Orthogonal experimental method was used to determine the best ratio of raw materials and the main factors which affect the structure and properties of films. The surface and optical properties of the films prepared by the best ratio of raw materials were measured. The results showed that the amount of TEOS is the greatest influence factor of transmittance, the amount of H2O is the greatest influence factor of reflectance, the aging time is the greatest influence factor of refractive index, the amount of EtOH is the greatest influence factor of microhardness. And the optimum experiment plan is that the volume ratio of TEOS:H2O:EtOH is 6:3:20, aging time is 6 hours and pH is 3.2. Research of SiO2 film by sol-gel methodUse the optimum experiment plan to prepare the sol solutions and use the spin coating to prepare films. Analysis results of XRD, DSC and TEM show that the SiO2 film prepared by the optimum experiment plan is disordered and network structure. Analysis result of TG-DTG shows that the SiO2 gel has high thermostability. Analysis result of AFM shows that the surface of film after heat treatment is uniform and has no crack. Test result of optical property shows that the SiO2 film has antireflection. Test result of mechanical property shows that the SiO2 film enhances the bending strength of samples.3. Research of Eu:SiO2 film by sol-gel methodDope EuCl3 when preparing the sol solutions with the doping content of 0.25%,0.5%,0.75% and 1%. Analysis result of DSC shows that the film is easier to crystallize with increase of the doping content. Analysis result of TG-DTG shows that the final products are not only SiO2, but also crystals. Analysis results of XRD and TEM both corroborate the result of thermal analysis. Contrast the PDF cards and it is possible to know that the crystals are Eu2Si2O7 and a-EuSiO3. Analysis result of PL shows that during heat treatment part of Eu3+ reduces to Eu2+. Analysis result of AFM shows that the surface smoothness of film after heat treatment is improved. Test result of contact angle measurement shows that Eu3+-doped can improve the hydrophilicity of the film. Test result of optical performance shows that the Eu:SiO2 film has influence on both bending strength and surface hardness of samples. Both bending strength and surface hardness have maximum values when the doping content is 0.5%. Test result of mechanical property shows that the Eu:SiO2 film enhances the transmittance of samples. And the transmittance has maximum values when the doping content is 0.5%.4. Research of multilayer film by sol-gel methodAnalysis result of SEM shows that films and the substrates combined closely after multilayer coating, and there is no significant gap between them. Use DMA to test the bending strength of solar cells. The result shows that when layer number is greater than six, the bending strength increases significantly. Eu:SiO2 film enhances the bending strength of solar cells, and the increased range is more significant than which enhanced by SiO2 film. The increased range of bending strength which enhanced by SiO2+Eu:SiO2 film is the superposition of SiO2 film and Eu:SiO2 film. Test result of contact angle measurement shows that the hydrophilicity of SiO2+ Eu:SiO2 film is worse than the hydrophilicity of Eu:SiO2 film and better than the hydrophilicity of SiO2 film.