Large change of visible transmittance with VO2 phase transition in VO2/TiO2 polycrystalline films

Wang, Haiyang; He, Weiji; Yuan, Guoliang; Wang, Xianya; Chen, Qian

doi:10.1016/j.tsf.2013.06.003

Cited by 13 publications

(9 citation statements)

References 20 publications

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“…Additionally, other oxides of vanadium, most notably vanadium(IV) oxide, VO 2 , have been used in composites with TiO 2 , although much of this research is limited due to the inherent instability of the lower oxides. However, because of the considerable amount of research regarding the thermochromic transition of VO 2 , − composites with TiO 2 have been investigated to enhance both the chemical stability of VO 2 and the transmittance, with some good results to date, − including a slight decrease in the transition temperature, though it still remains too high for practical use.…”

Section: Metal and Metal Oxide–tio2 Compositesmentioning

confidence: 99%

Composite Titanium Dioxide Nanomaterials

2014

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Figure 6. (a) Total organic carbon (TOC) removal during MB degradation. (b) XRD pattern showing evolution of crystal phase with increasing tungsten oxide content. (c) XPS fitting spectrum of 3% WO x −TiO 2 powder showing W 4f: arrows indicate the presence of WO 3 , W 6+ 4f spectrum, W x O y a mixed spectrum of W 5+ and W 6+ , and WO 2 W 4+ 4f. Adapted from ref 174, with permission from Elsevier.

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Section: Metal and Metal Oxide–tio2 Compositesmentioning

confidence: 99%

Composite Titanium Dioxide Nanomaterials

2014

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“…It should be noted that such coatings may be desired not only for oxidation protection but for their optical functionality. Thus the top coating can provide anti-reflection and thereby enhance the luminous transmittance, which is advantageous for windows-related applications [11,16], and studies have been reported for anti-reflecting layers based on oxides of Si [32][33][34][35][36][37], Ti [36][37][38][39][40][41][42], Zr [43] and Al [37]. It is likely that some or all of these oxide layers are able to impart oxidation protection of the underlying VO 2 .…”

Section: Conclusion and Remarksmentioning

confidence: 99%

Durability of thermochromic VO2 thin films under heating and humidity: Effect of Al oxide top coatings

Niklasson

et al. 2014

Thin Solid Films

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An explorative study was performed on sputter-deposited thermochromic (TC) VO 2 films exposed to heat treatment under dry and humid conditions. The ambient conditions were harsh and 80-nm-thick VO 2 films rapidly converted to non-TC V 2 O 5 . It was found that a 30-nm-thick sputter-deposited Al oxide top coating provided good protection and delayed the oxidation for more than one day upon heating in dry air at 300 °C and that protection occurred for several days at 95 % relative humidity and 60 °C. The thickness of the Al oxide was important and, expectedly, increased thickness yielded enhanced protection. Our results are important for TC fenestration as well as for other technical applications.

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“…This wide variation of the internal mechanical stress across the PT has been recently exploited to realize tunable microelectromechanical systems (MEMS), like programmable resonators and static actuators. [46][47][48][49][50][51] We note that the mechanical spectra of the microresonator, reported in Figure 1c, differ from that of the simple double-clamped beam model. This is because, as discussed in Section II (Supporting Information), the device profile has a slightly buckled shape due to the builtin compressive stress within the heterostructure.…”

Section: Actuatorsmentioning

confidence: 94%

“…As a consequence, the device experiences the stress-stiffening [40] and geometric-stiffening [41] effects, where the first is related to an increase of the tension within the structure and the second is a geometric deformation which both increase the structure rigidity. This wide variation of the internal mechanical stress across the phase transition has been recently exploited to realize tunable MEMS, like programmable resonators and static actuators [42][43][44][45][46][47]. We note that the mechanical spectra of the microresonator, reported in Fig.…”

mentioning

confidence: 97%

Selective High‐Frequency Mechanical Actuation Driven by the VO₂ Electronic Instability

et al. 2017

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This is the pre-peer reviewed version of the following article: "N. Manca et al. Adv. Mater. 29 (4), 1701618 (2017)", which has been published in final form at: http: //doi.wiley.com/10.1002/adma.201701618. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Ultra-thin free-standing structures such as membranes or microbridges can efficiently couple their mechanical degrees of freedom to electronic, optical and magnetic interactions in different excitation/response schemes [1][2][3][4]. The use of materials with intrinsic functionalities and complex response to external stimuli constitutes the keystone towards next-generation miniaturized sensors and actuators [5][6][7][8]. To this purpose, transition metal oxides are a unique class of materials, where the balance between electronic correlations, magnetic ordering and lattice distortions gives rise to phase transitions and nonlinear behaviours [9,10]. Among them, VO 2 is considered a textbook example due to its metal-insulator transition associated with a crystal symmetry change when its temperature is increased above 65 • C [11]. The phase transition of VO 2 is at the same time a puzzling mix of Mott physics, structural distortions [12][13][14][15] and a unique candidate for a variety of technological applications [16][17][18][19][20][21]. One of the most fascinating characteristics of VO 2 is the possibility of realizing a current/voltage periodic instability under constant electrical bias that determines electrical oscillations. Spontaneous oscillations are a hallmark of non-linear systems [22], and in VO 2 they are triggered by the strong non-linear variation of its electrical properties across the phase transition. This oscillating state has been investigated in VO 2 bulk crystals [23,24] and more recently in single-crystal nano-beams and thin films [25,26]. Several studies showed how it is possible to control the frequency and the onset of this oscillating state by external parameters, such as device geometry, electrical bias, laser heating or by connecting electrical passive elements [27][28][29][30]. So far all these studies focused on the analysis of the electrical characteristics of this oscillating state, considering it a potential platform for neural-mimicking computing architectures [31][32][33][34]. However, since the phase transition of VO 2 involves both its electronic and lattice properties, electrical oscillations shall also determine a strong periodic mechanical forces on the device structure, whose implications have not been studied so far. * n.manca@tudelft.nl; nicola.manca@spin.cnr.itHere, we demonstrate how the coupled resistive and structural transition of VO 2 can be employed to generate mechanical excitations in the MHz range using only a DC voltage source. This is a local self-actuation mechanism capable of driving the motion of a micro-mechanical resonator, performing a direct transduction from a voltage bias to high-frequency mechanical excitation which relies on the ...

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Large change of visible transmittance with VO2 phase transition in VO2/TiO2 polycrystalline films

Cited by 13 publications

References 20 publications

Composite Titanium Dioxide Nanomaterials

Composite Titanium Dioxide Nanomaterials

Durability of thermochromic VO2 thin films under heating and humidity: Effect of Al oxide top coatings

Selective High‐Frequency Mechanical Actuation Driven by the VO₂ Electronic Instability

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Large change of visible transmittance with VO2 phase transition in VO2/TiO2 polycrystalline films

Cited by 13 publications

References 20 publications

Composite Titanium Dioxide Nanomaterials

Composite Titanium Dioxide Nanomaterials

Durability of thermochromic VO2 thin films under heating and humidity: Effect of Al oxide top coatings

Selective High‐Frequency Mechanical Actuation Driven by the VO2 Electronic Instability

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Selective High‐Frequency Mechanical Actuation Driven by the VO₂ Electronic Instability