Title :
Improvement of electrochromic coloration efficiency by oxygen deficiency in sputtering a-WOx films
Author :
Ho, J.-J. ; Chen, C.Y. ; Lee, W.J.
Author_Institution :
Dept. of Electr. Eng., Nat. Taiwan Ocean Univ., Keelung, Taiwan
fDate :
4/15/2004 12:00:00 AM
Abstract :
Experimental results show that the coloration efficiency value and its light modulation capability of oxygen partial pressure at the optimum 6.5×10-3 torr are improved about tenfold and 234%, respectively, better than that at 2.0×10-3 torr of amorphous tungsten oxide (a-WOx) films by oxygen deficient stoichiometries, thus offering good electrochromic performance for opto-switching applications. It is concluded that the optical absorption of a coloured a-WOx film can be satisfactorily described by an intervalence charge-transfer transition mechanism between localised W5+ and W6+ states.
Keywords :
amorphous semiconductors; charge transfer states; electrochromic devices; electrochromism; optical modulation; semiconductor growth; semiconductor thin films; sputter deposition; stoichiometry; tungsten compounds; valency; visible spectra; 2.0×10-3 torr; 6.5×10-3 torr; ITO coated glass substrates; InSnO-SiO2Jk; WOx; amorphous WOx films; amorphous tungsten oxide films; electrochromic coloration efficiency; intervalence charge transfer transition mechanism; light modulation capability; localised states; optical absorption; opto-switching applications; oxygen deficient stoichiometry; oxygen partial pressure; sputtering;
Journal_Title :
Electronics Letters
DOI :
10.1049/el:20040290
