DOI QR코드

DOI QR Code

Transparent Hydrophobic Anti-Reflection Coating with SiO2\TiO2 Thin Layers

SiO2\TiO2 박막에 의한 투명 발수 반사방지 코팅

  • Noh, Yeoung-Ah (Department of Advanced Materials Science and Engineering, Hanyang University) ;
  • Kim, Ki-Chul (Department of Advanced Chemical Engineering, Mokwon University)
  • 노영아 (한양대학교 첨단소재공학과) ;
  • 김기출 (목원대학교 신소재화학공학과)
  • Received : 2016.11.11
  • Accepted : 2017.03.10
  • Published : 2017.03.31

Abstract

Functional coatings, such as anti-reflection and self-cleaning, are frequently applied to cover glass for photovoltaic applications. Anti-reflection coatings made of mesoporous silica film have been shown to enhance the light transmittance. $TiO_2$ photocatalyst films are often applied as a self-cleaning coating. In this study, transparent hydrophobic anti-reflective and self-cleaning coatings made of $SiO_2/TiO_2$ thin layers were fabricated on a slide glass substrate by the sol-gel and dip-coating processes. The morphology of the functional coatings was characterized by field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). The optical properties of the functional coatings were investigated using an UV-visible spectrophotometer. Contact angle measurements were performed to confirm the hydrophobicity of the surface. The results showed that the $TiO_2$ films exhibit a high transmittance comparable to that of the bare slide glass substrate. The $TiO_2$ nanoparticles make the film more reflective and lead to a lower transmittance. However, the transmittance of the $SiO_2/TiO_2$ thin layers is 93.5% at 550 nm with a contact angle of $110^{\circ}$, which is higher than that of the bare slide glass (2.0%).

태양전지의 셀을 보호하기 위한 커버 글라스에는 반사방지 코팅 및 셀프클리닝과 같은 기능성 코팅이 적용되어왔다. 일반적으로 메조포러스 실리카를 이용한 반사방지 코팅은 빛의 투과를 증가시키며, $TiO_2$ 광촉매 필름은 셀프클리닝 코팅에 적용되어왔다. 본 연구에서는 $SiO_2/TiO_2$ 박막 코팅에 의한 투명 발수 반사방지 및 셀프클리닝 코팅을 sol-gel 공정과 dip-coating 공정으로 글라스 기판 위에 제조하였다. 기능성 코팅의 표면형상은 전계방출 주사전자현미경과 원자힘 현미경으로 분석하였고, 광학적 특성은 UV-visible 분광광도계로 분석하였다. 필름의 발수특성은 접촉각 측정으로 확인하였다. 그 결과 $TiO_2$ 필름은 기판인 슬라이드 글라스와 비슷한 수준의 높은 광 투과율을 나타내었다. 일반적으로 $TiO_2$ 나노입자는 필름에서 반사를 증가시키며, 결과적으로 투과율의 저하를 가져온다. 하지만 본 연구의 $SiO_2/TiO_2$ 박막으로 이루어진 기능성 코팅은 $110^{\circ}$의 접촉각을 나타내었으며, 파장 550 nm에서 기판인 슬라이드 글라스의 투과율보다 2.0% 증가한 93.5%의 광 투과율 특성을 나타내었다.

Keywords

References

  1. D. Lee, M. F. Rubner, and R. E. Cohen, "All-Nanoparticle Thin Film Coatings", Nano Letters, Vol. 6, No. 10, pp. 2305-2312, 2006. DOI: https://doi.org/10.1021/n1061776m
  2. R. Prado, G. Beobide, A. Marcaide, J. Goikoetxea, and A. Aranzabe, "Development of multifuntional sol-gel coatings: Anti-reflection coatings with enhanced self-cleaning capacity" Solar Energy Mterials & Solar Cells, Vol. 94, pp. 1081-1088, 2010. DOI: https://doi.org/10.1016/j.solmat.2010.02.031
  3. M. Faustini, L. Nicole, C. Boissiere, P. Innocenzi, C. Sanchez, and D. Grosso, "Hydrophobic, Antireflective, Self-Cleaning, and Antifogging Sol-Gel Coatings: An Example of Mutifuntional Nanostructured Materials for Phtovoltaic Cells" Chemistty of Materials, Vol. 22, pp. 4406-4413, 2010. DOI: https://doi.org/10.1021/cm100937e
  4. O. Kesmez, H. E. Camurlu, E. Burunkaya, and E. Arpay, "Sol-gel preparation and characterization of anti-reflective and self-cleaning $SiO_2-TiO_2$ double-layer nanometric films ", Solar Energy Materials & Solar Cells, Vol. 93, pp. 1833-1839, 2009. DOI: https://doi.org/10.1016/j.solmat.2009.06.022
  5. S-Y. Lien, D-S. Wuu, W-C Yeh, and J-C Liu, "Tri-layer antireflection coatings ($SiO_2$/$SiO_2-TiO_2$/$Ti0_2$) for silicon solar cells using a sol-gel technique" Solar Energy Materials & Solar Cells, Vol. 90, pp. 2710-2719, 2006. DOI: https://doi.org/10.1016/j.solmat.2006.04.001
  6. S. Chhajed, M. F. Schubert, J. K. Kim, and E. F. Schubert, "Nanostructured multilayer graded-index anti-reflection coating for Si solar cells with broadband and omnidirectional characteristics" , Applied Physics Letters, Vol. 93 , p. 251108, 2008. DOI: https://doi.org/10.1063/1.3050463
  7. M-L. Kuo, D. J. Poxson, Y. S. Kim, F. W. Mont, J. K. Kim, E. F. Schubert, and S-Y. Lin, "Realization of a near-perfect antireflection coating for silicon solar energy utilization", Optics Express, Vol. 33, No. 21 , pp 2527-2529, 2008. DOI: https://doi.org/10.1364/01.33.002527
  8. J. Moghal, S. Reid, L. Hagerty, M. Gardener, and G. Wakefield, "Development for single layer nanoparticle anti-reflection coating for polymer substrates", Thin Solid Films, Vol. 534 pp. 541-545, 2013. DOI: https://doi.org/10.1016/j.tsf.2013.03.005
  9. J. Moghal, J. Kobler, J. Sauer, J. Best, M. Gardener, A. A. R. Watt, and G. Wakefield, "High-Performance, Single-Layer Antireflective Optical Coatings Comprising Mesoporous Silica Nanoparticles", ACS Applied Materials & Interfaces, Vol. 4, pp. 854-859, 2012. DOI: https://doi.org/10.10211am201494m https://doi.org/10.1021/am201494m
  10. K-S. Han, H. Lee, D. Kim, and H. Lee, "Fabrication of anti-reflection structure on protective layer solar cells by hot-embossing method", Solar Energy Materials & Solar Cells, Vol. 93, pp. 1214-1217, 2009. DOI: https://doi.org/10.1016/j.solmat.2009.01.002
  11. Y. Li, J. Zhang, and B. Yang, "Antireflective surfaces based on biomimetic nanopillared array", Nanotoday, Vol. 5, pp. 117-127, 2010. DOI: https://doi.org/10.1016/j.nantod.2010.03 .001
  12. W. Choi, "Studies on $TiO_2$ Photocatalytic Reactions", Journal of The Korean Industrial and Engineering Chemistry, Vol. 14, No. 8, pp. 1011-1022, 2003.
  13. H-H. Jung, J-H. Kim, J. Hwang, T-Y. Lim, and D-G. Choi, "Fabrication of super hydrophilic $TiO_2$ thin film by a liquid phase deposition", Journal of the Korean Crystal Growth and Crystal Technology, Vol. 20, No. 5, pp. 227-231, 2010. DOI: https://doi.org/10.6111/JKCGCT.2010.20.5.227
  14. A. Nakajima, K. Hashimoto, and T. Watanabe, "Transparent Superhydrophobic Thin Films with Self-Cleaning Properties" Langmuir, Vol. 16, pp. 7044-7047, 2000. DOI: https://doi.org/10.10211/a000155k
  15. H. Zhang, D. Fan, T. Yu, and C Wang, "Characterization of anti-reflective and self-cleaning $SiO_2-TiO_2$ composite film", Journal of Sol-Gel Science and Technology, Vol. 66, pp. 274-279, 2013. DOI: https://doi.org/10.1007/s10971-013-3004-y
  16. W. Glaubitt, and P. Lobmann, "Anti-soiling effect of porous $SiO_2$ coatings prepared by sol-gel processing", Journal of Sol-Gel Science and Technology, Vol. 59, pp. 239-244, 2011. DOI: https://doi.org/10.1007/s10971-011-2489-5
  17. A. Shokuhfar, M. Alzamani, E. Eghdam, M. Karimi, and S. Mastali, "$SiO_2TiO_2$ Nanostructure Films on Windshields Prepared by Sol-Gel Dip-Coating Technique for Self-Cleaning and Photocatalytic Applications", Nanoscience and Nanotechnology, Vol. 2, No. 1, pp. 16-21, 2012. DOI: https://doi.org/10.5923/j.ml.20120201.04
  18. F. Li, Q. Li, and H. Kim, "Spray deposition of electrospun $TiO_2$ nanoparticles with self-cleaning and transparent properties onto glass" , Applied Surface Science, Vol. 276, pp. 390-396, 2013. DOI: https://doi.org/10.1016/j.apsusc.2013.03.103