Effect of O2 flow rate on the electrochromic response of WO3 grown by LPCVD

Tungsten trioxide coatings were grown on fluorine doped tin dioxide glass substrate at 465 oC by low pressure chemical vapor deposition. Monoclinic tungsten oxide with low crystallinity containing agglomeration of grains was obtained irrespective of the O2 flow rate utilized. It was only observed an increase of grain size to 75 from 25 nm as the O2 raised to 100 from 25 sccm. In addition, the current density was similar among the samples irrespective of the growth conditions performed. Finally, the coloration efficiency was estimated to be 83 cm2 C-1 at 670 nm, which is higher than other grown samples using greater deposition temperatures. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)