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Synthesis of Anti-reflection and Self-cleaning Coating on Glass Substrate Using Sol-gel Method

Sharifi Rad, Alireza | 2018

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 50567 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Afshar, Abdollah
  7. Abstract:
  8. Using of solar spectrum because of its potential for producing green energy is the topic of interest in Current decade. The goal of current research is increment of efficiency by using of a single layer and double layer semiconductor TiO2 – ZnO coating that has been synthesized by sol-gel process, which have anti-reflation and self-cleaning properties that in short time and long time for durability of solar systems can be useful. In first step of this research the single layer TiO2 (by 85nm thickness, measured by FE-SEM) and ZnO (by 65nm thickness) coating with different concentrations of pore forming agents ( plironic f127 for TiO2 and CTAB for ZnO) in coating sol examined and observed that in TiO2 coating with increasing the f127 concentration , the refractive index reduced and also the transparency of the coating in visible spectrum was increased about 0.5% in comparison with bare glass that has been shown by spectrophotometry. For ZnO single layers, with increasing of pore forming agent concentration to 2*10-2 , the transparency of coated sample was reached to the maximum amount but by calculation of refractive index observed that the refractive index of the coating decreased by increasing the concentration of pore forming agent to 4*10-2.atomic force microscopy showed that the RMS of coating surface increased by adding the pore forming agent in TiO2 coating that helps light trapping in roughed anti-reflection coatings. by steady the refractive index of single layers and its realetionship with pore forming agent , double layer coatings designed that the optimum double leyer coating has the pore forming agent free ZnO lower layer and the upper layer was TiO2 coating by 1.6 * 10-3 M of pore forming agent that decreased the reflectance of coated sample about 2% in visible spectrum comparing to bare glass. Etching was another method that modified the transparency of coated sample about 2.5% by 20s etching in HF 5% solution that this phenomenon observed for single layer and double layer coating. Study of self-cleaning properties of coatings showed that the surface contact angle of coating (5.8°) was in super-hydrophilic coating zone and by increasing the concentration of pore forming agent to 1.6 * 10-3, the contact angle decreased to 4.2°. the decomposition of organic pollution (stearic acid) was Checked out by contact angle and transparency measurement and showed that reduction of transparency and hydrophilic properties ( because of pollution) recovered after 30 to 60 minute UV irradiation by photodecomposition of stearic acid
  9. Keywords:
  10. Sol-Gel Method ; Self-Cleaning ; Titanium Oxide Coating ; Anti Reflection Coating

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