Synthesis of Tungsten-Doped Vanadium Dioxide Using a Modified Polyol Method Involving 1-Dodecanol
The doping of tungsten into VO (M) via a polyol process that is based on oligomerization of ammonium metavanadate and ethylene glycol (EG) to synthesize a vanadyl ethylene glycolate (VEG) followed by postcalcination was carried out by simply adding 1-dodecanol and the tungsten source tungstenoxytetr...
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Published in | Materials Vol. 13; no. 23; p. 5384 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Switzerland
MDPI AG
27.11.2020
MDPI |
Subjects | |
Online Access | Get full text |
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Summary: | The doping of tungsten into VO
(M) via a polyol process that is based on oligomerization of ammonium metavanadate and ethylene glycol (EG) to synthesize a vanadyl ethylene glycolate (VEG) followed by postcalcination was carried out by simply adding 1-dodecanol and the tungsten source tungstenoxytetrachloride (WOCl
). Tungsten-doped VEGs (W-VEGs) and their calcinated compounds (W
VO
) were prepared with varying mixing ratios of EG to 1-dodecanol and WOCl
concentrations. Characterizations of W-VEGs by powder X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and infrared and transmittance spectroscopy showed that tungsten elements were successfully doped into W
VO
, thereby decreasing the metal-insulator transition temperature from 68 down to 51 °C. Our results suggested that WOCl
variously combined with 1-dodecanol might interrupt the linear growth of W-VEGs, but that such an interruption might be alleviated at the optimal 1:1 mixing ratio of EG to 1-dodecanol, resulting in the successful W doping. The difference in the solar modulations of a W
VO
dispersion measured at 20 and 70 °C was increased to 21.8% while that of a pure VO
dispersion was 2.5%. It was suggested that WOCl
coupled with both EG and 1-dodecanol at an optimal mixing ratio could improve the formation of W-VEG and W
VO
and that the bulky dodecyl chains might act as defects to decrease crystallinity. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1996-1944 1996-1944 |
DOI: | 10.3390/ma13235384 |