A Study on the Optical Properties of Lithium Injection in V$_2$O$_{5}$ Electrochromic Thin Films

리튬이 주입된 전기변색 V$_2$O$_{5}$ 박막의 광 특성에 관한 연구

  • Ha, Seung-Ho (Dept. of Electronic Materials Engineering, The Universityof Suwon) ;
  • Cho, Bong-Hee (Dept. of Electrical Engineering, The University of Suwon) ;
  • Kim, Young-Ho (Dept. of Electronic Materials Engineering, The Universityof Suwon)
  • 하승호 (수원대학교 전자재료공학과) ;
  • 조봉희 (수원대학교 전기공학과) ;
  • 김영호 (수원대학교 전자재료공학과)
  • Published : 1995.10.01


The electrochromic properties of vacuum deposited V$_2$O$_{5}$ thin films as a function of crystallinity and film thickness have been systematically investigated. The as-deposited films have slightly yellow appearance. V$_2$O$_{5}$ films deposited at higher substrate temperature(>14$0^{\circ}C$) are found to be crystalline while those deposited at low substrate temperature are amorphous. The optical modulation on lithium ion injection indicates that V$_2$O$_{5}$ films exhibit anodic coloration in the 300~500 nm wavelength range and cathodic coloration in the 500~1100nm wavelength range independent of crystallinity and film thickness. The optical band gap energy of crystalline and amorphous Li$_{x}$ VV$_2$O$_{5}$ films shifts to higher energies by 0.17 eV and 0.75 eV, respectively, with increasing lithium ion injection up to x=0.6. The coloration efficiency of amorphous Li$_{x}$ V$_2$O$_{5}$ exhibits very little dependence on film thickness and lithium ion injection amounts in the near-infrared while it increases significantly with increasing film thickness and decreasing lithium ion injection amounts in the blue and near-UV due to the shift in absorption edge below around 500nm. However, the coloration efficiency of crystalline Li$_{x}$ V$_2$O$_{5}$is relatively independent of film thickness and lithium ion injection in the 300~1100 nm wavelength range.



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