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Synthesis and characterization of VO2-based thermochromic thin films for energy-efficient windows.

Batista C, Ribeiro RM, Teixeira V - Nanoscale Res Lett (2011)

Bottom Line: Moreover, the effectiveness of each dopant element on the reduction of the intrinsic transition temperature and infrared modulation efficiency of VO2 is discussed.The dopants effectively decreased the transition of VO2 to the proximity of room temperature.Tungsten proved to be the most effective element on the reduction of the semiconducting-metal transition temperature, while Mo and Nb showed similar results with the latter being detrimental to the thermochromism.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal. cbatista@fisica.uminho.pt.

ABSTRACT
Thermochromic VO2 thin films have successfully been grown on SiO2-coated float glass by reactive DC and pulsed-DC magnetron sputtering. The influence of substitutional doping of V by higher valence cations, such as W, Mo, and Nb, and respective contents on the crystal structure of VO2 is evaluated. Moreover, the effectiveness of each dopant element on the reduction of the intrinsic transition temperature and infrared modulation efficiency of VO2 is discussed. In summary, all the dopant elements--regardless of the concentration, within the studied range-- formed a solid solution with VO2, which was the only compound observed by X-ray diffractometry. Nb showed a clear detrimental effect on the crystal structure of VO2. The undoped films presented a marked thermochromic behavior, specially the one prepared by pulsed-DC sputtering. The dopants effectively decreased the transition of VO2 to the proximity of room temperature. However, the IR modulation efficiency is markedly affected as a consequence of the increased metallic character of the semiconducting phase. Tungsten proved to be the most effective element on the reduction of the semiconducting-metal transition temperature, while Mo and Nb showed similar results with the latter being detrimental to the thermochromism.

No MeSH data available.


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Relationship between the dopant contents in the film and the resultant semiconductor-metal phase transition temperature.
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Figure 3: Relationship between the dopant contents in the film and the resultant semiconductor-metal phase transition temperature.

Mentions: The effectiveness of each dopant on the reduction of the semiconducting-metal transition temperature in VO2 is compared in Figure 3. All the three elements showed a linear decrease of the transition temperature with the increase in the concentration of substitutional doping element. Tungsten is clearly the most effective dopant element showing a decrease of about 7°C per at.%. Mo and Nb showed nearly the same results, about 3 and 2°C, per at % Mo and Nb, respectively.


Synthesis and characterization of VO2-based thermochromic thin films for energy-efficient windows.

Batista C, Ribeiro RM, Teixeira V - Nanoscale Res Lett (2011)

Relationship between the dopant contents in the film and the resultant semiconductor-metal phase transition temperature.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211368&req=5

Figure 3: Relationship between the dopant contents in the film and the resultant semiconductor-metal phase transition temperature.
Mentions: The effectiveness of each dopant on the reduction of the semiconducting-metal transition temperature in VO2 is compared in Figure 3. All the three elements showed a linear decrease of the transition temperature with the increase in the concentration of substitutional doping element. Tungsten is clearly the most effective dopant element showing a decrease of about 7°C per at.%. Mo and Nb showed nearly the same results, about 3 and 2°C, per at % Mo and Nb, respectively.

Bottom Line: Moreover, the effectiveness of each dopant element on the reduction of the intrinsic transition temperature and infrared modulation efficiency of VO2 is discussed.The dopants effectively decreased the transition of VO2 to the proximity of room temperature.Tungsten proved to be the most effective element on the reduction of the semiconducting-metal transition temperature, while Mo and Nb showed similar results with the latter being detrimental to the thermochromism.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal. cbatista@fisica.uminho.pt.

ABSTRACT
Thermochromic VO2 thin films have successfully been grown on SiO2-coated float glass by reactive DC and pulsed-DC magnetron sputtering. The influence of substitutional doping of V by higher valence cations, such as W, Mo, and Nb, and respective contents on the crystal structure of VO2 is evaluated. Moreover, the effectiveness of each dopant element on the reduction of the intrinsic transition temperature and infrared modulation efficiency of VO2 is discussed. In summary, all the dopant elements--regardless of the concentration, within the studied range-- formed a solid solution with VO2, which was the only compound observed by X-ray diffractometry. Nb showed a clear detrimental effect on the crystal structure of VO2. The undoped films presented a marked thermochromic behavior, specially the one prepared by pulsed-DC sputtering. The dopants effectively decreased the transition of VO2 to the proximity of room temperature. However, the IR modulation efficiency is markedly affected as a consequence of the increased metallic character of the semiconducting phase. Tungsten proved to be the most effective element on the reduction of the semiconducting-metal transition temperature, while Mo and Nb showed similar results with the latter being detrimental to the thermochromism.

No MeSH data available.


Related in: MedlinePlus