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Thermochromic VO2 thin films deposit...

Fortier, Jean-Philippe.

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Thermochromic VO2 thin films deposited by magnetron sputtering for smart window applications.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Thermochromic VO2 thin films deposited by magnetron sputtering for smart window applications./
Author:	Fortier, Jean-Philippe.
Description:	137 p.
Notes:	Source: Masters Abstracts International, Volume: 54-04.
Contained By:	Masters Abstracts International54-04(E).
Subject:	Materials science. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=1690669
ISBN:	9781321613391

Thermochromic VO2 thin films deposited by magnetron sputtering for smart window applications.
Fortier, Jean-Philippe.

Thermochromic VO2 thin films deposited by magnetron sputtering for smart window applications. - 137 p.

Source: Masters Abstracts International, Volume: 54-04.

Thesis (M.Sc.A.)--Ecole Polytechnique, Montreal (Canada), 2014.

This item must not be sold to any third party vendors.

"Smart" windows are a perfect innovative example of technology that reduces our energy dependence and our impact on the environment while saving on the economical point of view. With the use of vanadium dioxide (VO2), a thermochromic compound, and this, as a thin coating, it would in fact be possible to control the sun's transmission of infrared light (heat) as a function of the surrounding environment temperature. In other words, its optical behavior would allow a more effective management of heat exchanges between a living venue and the outdoor environment. However, this type of window is still in a developmental stage. First, the oxide's deposition is not simple in nature. Based on a conventional deposition technique called magnetron sputtering mainly used in the fenestration industry, several factors such as the oxygen concentration and the substrate temperature during deposition can affect the coating's thermochromic behavior, and this, by changing its composition and crystallinity. Other control parameters such as the deposition rate, the pressure in the sputtering chamber and the choice of substrate may also modify the film microstructure, thereby varying its optical and electrical properties. In addition, several issues still persist as to its commercial application. For starters, the material's structural transition, related to the change of its optical properties, only occurs around 68°C. In addition, its low transparency and natural greenish colour are not visually appealing. Then, to this day, the deposition temperature required to crystallize and form the thermochromic oxide remains an obstacle for a possible large-scale application. Ultimately, although the material's change in temperature has been shown to be advantageous in situations of varying climate, the existing corrective solutions to these issues generate a deterioration of the thermochromic behavior.

ISBN: 9781321613391Subjects--Topical Terms:

543314
Materials science.

Thermochromic VO2 thin films deposited by magnetron sputtering for smart window applications.
LDR:06321nmm a2200337 4500 001 2062493
005 20151027073328.5
008 170521s2014 ||||||||||||||||| ||eng d
020 $a 9781321613391
035 $a (MiAaPQ)AAI1690669
035 $a AAI1690669
040 $a MiAaPQ $c MiAaPQ
100 1 $a Fortier, Jean-Philippe. $3 3176880
245 1 0 $a Thermochromic VO2 thin films deposited by magnetron sputtering for smart window applications.
300 $a 137 p.
500 $a Source: Masters Abstracts International, Volume: 54-04.
500 $a Advisers: Ludvik Martin; Jolanta-Ewa Klemberg-Sapieha.
502 $a Thesis (M.Sc.A.)--Ecole Polytechnique, Montreal (Canada), 2014.
506 $a This item must not be sold to any third party vendors.
506 $a This item must not be added to any third party search indexes.
520 $a "Smart" windows are a perfect innovative example of technology that reduces our energy dependence and our impact on the environment while saving on the economical point of view. With the use of vanadium dioxide (VO2), a thermochromic compound, and this, as a thin coating, it would in fact be possible to control the sun's transmission of infrared light (heat) as a function of the surrounding environment temperature. In other words, its optical behavior would allow a more effective management of heat exchanges between a living venue and the outdoor environment. However, this type of window is still in a developmental stage. First, the oxide's deposition is not simple in nature. Based on a conventional deposition technique called magnetron sputtering mainly used in the fenestration industry, several factors such as the oxygen concentration and the substrate temperature during deposition can affect the coating's thermochromic behavior, and this, by changing its composition and crystallinity. Other control parameters such as the deposition rate, the pressure in the sputtering chamber and the choice of substrate may also modify the film microstructure, thereby varying its optical and electrical properties. In addition, several issues still persist as to its commercial application. For starters, the material's structural transition, related to the change of its optical properties, only occurs around 68°C. In addition, its low transparency and natural greenish colour are not visually appealing. Then, to this day, the deposition temperature required to crystallize and form the thermochromic oxide remains an obstacle for a possible large-scale application. Ultimately, although the material's change in temperature has been shown to be advantageous in situations of varying climate, the existing corrective solutions to these issues generate a deterioration of the thermochromic behavior.
520 $a With no practical expertise on the material, this project was undertaken with certain objectives in mind. To start, we had to find a first recipe to obtain our first samples of the material. Using the literature as a starting point, several samples were deposited by magnetron sputtering while improving certain deposition conditions as well as varying influential deposition parameters. Once the oxide obtained, it was necessary to optimize the parameters not only to render thermochromic coatings with the highest possible quality, but also to determine each parameter's sensitivity. Characterization techniques such as microscopy, spectroscopy, ellipsometry, scanning electron microscopy, atomic force microscopy, Raman spectroscopy, x-ray diffraction and finally, time-of-flight secondary ion mass spectrometry were used to analyze different aspects of our multiple samples. Indeed, to mention only the ix most relevant observations, we were able to confirm that the microstructure, composition, most relevant observations, we were able to confirm that the microstructure, composition, crystallinity and film thickness have a significant impact on the coating's thermochromic behavior as well as on its optical properties. As a result, the oxygen concentration and the thickness had to be optimized and the deposition temperature, maximized. Reactive poisoning of the sputtering target is also a phenomenon that needs to be considered during deposition. Then, our sputtering target and substrate cleaning procedures were improved following certain observations. VO2 was equally found to be sensitive to small temperature gradients in addition of being highly dependent upon high deposition temperatures. Finally, the use of different substrates has subsequently shown that the film composition and microstructure can be altered.
520 $a After mastering the deposition of thin VO2 films, we explored another path that we found to be quite innovative. A relatively new deposition technique called HiPIMS was put to the test based on its new characteristics, leading to believe that it had the potential of improving our coatings and allow a better application of the material. We first took some time to study and adapt to the technique's distinct characteristics, based on pulsed sputtering. After parameter optimization, the highly ionized sputtering flux allowed us to obtain more crystalline and denser coatings, with considerable homogeneity, less roughness and a higher purity than films obtained using conventional sputtering and than those described in the literature. With these features, it was possible to extract the material's optical constants and to obtain a change of transmission in the infrared (DeltaT2500 nm=61%) comparable to the best performing thermochromic samples documented in the literature, and this, at a substantially lower deposition temperature (300°C). This is a technical highlight, as conventional sputtering methods normally require temperatures above 400°C to form the oxide. In addition, our films had transition temperatures lower than that of the bulk material. The results seem to indicate that HiPIMS is promising and preferable for the deposition of VO2 films with respect to their practical use in the world of windows. (Abstract shortened by UMI.).
590 $a School code: 1105.
650 4 $a Materials science. $3 543314
650 4 $a Energy. $3 876794
650 4 $a Optics. $3 517925
690 $a 0794
690 $a 0791
690 $a 0752
710 2 $a Ecole Polytechnique, Montreal (Canada). $3 1018606
773 0 $t Masters Abstracts International $g 54-04(E).
790 $a 1105
791 $a M.Sc.A.
792 $a 2014
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=1690669