Study On SiO₂ Antireflective Coatings With Phosphoric Acid As Pore-forming Template

Photovoltaic cell anti reflective film?AR film? is an effective way to improve the efficiency of photovoltaic cells.In this paper, the feasibility of antireflective film where the phosphoric acid is used as template is studied. And the method of making sol and the coating process of antireflective film are further improved. The effects of phosphoric acid concentration, boiling water treatment and coating speed on antireflective films were studied. The optimum parameters of the phosphoric acid-templated films with high transmittance were investigated.After obtaining the best ratio and process, the effect of aging time on the sol and the transmittance of the sample after aging were further studied. As well as the changes of the sol's viscosity and the sample's surface morphology were investigated. For the wide application of such an antireflective film, a dip coating method was used in our work. The effect of coating speed on film thickness and sample transmittance was studied, and the optimum coating speed was found. The ultra-white embossed tempered glass was used as the glass substrate to study the dip-coating method of ultra-white embossed tempered glass. The transmittance curve, pencil hardness and adhesion of the ultra-white embossed tempered glass samples coated with antireflective films were tested. After research and discussion, the main conclusions are as follows:1. The inorganic pore-forming template H₃PO₄ can be used as a pore-forming agent in the hole-forming process of a porous antireflective film. And the transmittance of the obtained sample is considerably improved compared to the bare glass substrate.2. The boiling water bath can remove the H₃PO₄, the pore-forming template after the completion the pore-forming process, which can significantly improve the light transmittance. When boiling water bath is done, the transmittance is first increases the addition of H₃PO₄ and then decreases as the H₃PO₄ concentration decreases. The pore size of the pores in the antireflective film also decreases with the decreases of the H₃PO₄ .3. The aging time of the sol has a significant effect on the transmittance of the coated sample. With the increase of the aging time of the sol, the transmittance peak decreases gradually. However, the pore size of the pores, the number of the large pores and the viscosity of the sol increase.4. The withdraw speed has a significant effect on the thickness of the film. With the increase of the withdraw speed, the visible light maximum transmittance of samples increases and then it changes slightly within a certain range. After that, the maximum decrease gradually with the increase of the speed.5. The coating-deposited sample with the best transmitting performance was obtained by using the sol which is aged for 1 day and coating with a withdraw speed of 2000?m/s.And the coated sample with suitable AR film reaches up to a peak transmittance of 99.2%.6. With its particularity, to coating on the single side, ultra-white embossed tempered glass needs to be two pieces-bonding in the coating process. The transmittance of the ultrafine embossed tempered glass samples was increased first and then decreased, and the transmittance curve peaked at 93.72%. The pencil hardness of the ultra-white embossed tempered glass sample was tested for 3H achieving the national standard, and the adhesion test was qualified for grade 0.