2-Dimensional inverse opal structured VO2 thin film for selective reflectance adjustment

  • Lee, Yulhee (Department of Chemistry, Sungkyunkwan University) ;
  • Yu, Jung-Hoon (Department of Chemistry, Sungkyunkwan University) ;
  • Nam, Sang-Hun (Institute of Basic Science, Sungkyunkwan University) ;
  • Seo, Hyeon Jin (Department of Chemistry, Sungkyunkwan University) ;
  • Hwang, Ki-Hwan (Department of Chemistry, Sungkyunkwan University) ;
  • Kim, Minha (School of Electronic and Electrical Engineering, Sungkyunkwan University) ;
  • Lee, Jaehyeong (School of Electronic and Electrical Engineering, Sungkyunkwan University) ;
  • Boo, Jin-Hyo (Department of Chemistry, Sungkyunkwan University)
  • Published : 2016.02.17

Abstract

Vanadium dioxide ($VO_2$) is a well-known material that exhibits a metal-semiconductor transition at 340 K, with drastic change of transmittance at NIR region. However, $VO_2$ based thermochromics accompany with low visible transmittance value and unfavorable color (brownish yellow). Herein, we demonstrate the adjustment of visible transmittance of $VO_2$ thin film by nanosphere template assisted patterning process using sol-gel method. 2-Dimenstional honeycomb shape was varied as function of diameter of nanosphere and coating conditions. The morphological geometry of the films was investigated by FE-SEM and AFM. Result shows that inversed shape of nanosphere was formed clearly and pattern width was altered according to the bead size. This structure creates the geometrical blank area from the position of nanosphere which improves the optical transmittance at the visible region. Moreover, such patterned $VO_2$ thin film not only maintains the optical switching efficiency, but also generate the gorgeous scattering effect which presumably support the glazing application.

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