Synthesis and optical properties of vanadium dioxide nanoparticles in nanoporous glasses

Sidorov, A. I.; Vinogradova, O. P.; Obyknovennaya, I. E.; Khrushchova, T. A.

doi:10.1134/s1063785007070127

Cited by 10 publications

(8 citation statements)

References 5 publications

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“…Generally, spaces about 2−5 nm in width were observed between grains, and they were attributed to poorly crystallized phases and/or voids. It is widely reported that VO 2 films with second or amorphous phases at grain boundaries demonstrate a broadened hysteresis, which is definitely consistent with our experiments. ,,, …”

Section: Resultssupporting

confidence: 93%

“…The widths of the hysteresis loops are 39.8, 50, and 45.3 °C for samples I, II, and III, respectively. These widths are much larger than the typical values for continuous polycrystalline VO 2 films (10−15 °C, 3−20 °C, 6−18 °C, 8−15 °C) but are consistent with isolated VO 2 nanoparticles or with films composed of isolated nanoparticles (30−50 °C, 18 ± 2 °C and 56 ± 5 °C, 38 °C, 30 and 35 °C). The main factors that affect the S−M transition are crystallinity, grain size, and grain boundaries. ,, Prolonged annealing should improve crystallinity, resulting in hysteresis loop broadening .…”

Section: Resultssupporting

confidence: 69%

“…It is widely reported that VO 2 films with second or amorphous phases at grain boundaries demonstrate a broadened hysteresis, which is definitely consistent with our experiments. 17,31,36,54 Sample VIII, on the other hand, consisted of smooth connected particles and interconnected pores among particles (parts d and e of Figure 9). This morphology should be a result of mass transport and aggregation of the primary VO 2 crystals during annealing.…”

Section: Resultsmentioning

confidence: 99%

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Effects of Annealing Parameters on Optical Properties of Thermochromic VO₂ Films Prepared in Aqueous Solution

et al. 2010

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This work confirmed experimentally that the microstructure (grain boundaries, grain sizes, and size distributions) of VO 2 films has significant effects on the features of the semiconductor-metal (S-M) transition. This feature enables us to wisely regulate the parameters of the phase transition, which is of great importance in achieving practical applications. Thermochromic VO 2 films with various optical properties and phase transition parameters (for example: hysteresis widths ranging from 12 to 50 °C) have been synthesized on fused silica substrates via a simple solution process with inorganic precursors and polyvinylpyrrolidone (PVP). The widths and slopes of the hysteresis loops (i.e., the temperature sensitivity of the transition) can be regulated by controlling grain sizes and grain boundary conditions, which are believed to dominate the generation of the elementary hysteresis loop of each grain and the propagation of the S-M transition, respectively. A film consisting of qusai-isolated small particles shows a wide hysteresis loop due to the large interfacial energies and the lack of defects for nucleating. Besides, grain boundaries can decrease the interfacial energies and favor the phase propagation. In addition, particle sizes seem to influence the visible transmittances of these films effectively without deterioration of the infrared regulation ability. This experimental phenomenon is assigned to the blue shift of absorption edges (at around 500 nm) accompanying decreases in particle size.

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Section: Resultssupporting

confidence: 93%

Section: Resultssupporting

confidence: 69%

Section: Resultsmentioning

confidence: 99%

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Effects of Annealing Parameters on Optical Properties of Thermochromic VO₂ Films Prepared in Aqueous Solution

et al. 2010

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“…Generally, spaces about 2-5 nm in width were observed between grains, and they were attributed to poorly crystallized phases and/or voids. It is widely reported that VO 2 films with second or amorphous phases at grain boundaries demonstrate a broadened hysteresis, 82,93,94 which is definitely consistent with our experiments. Sample VIII, on the other hand, consisted of smooth connected particles and interconnected pores among particles (Figure 17d, e).…”

Section: The Methodssupporting

confidence: 82%

Solution Processing of Nanoceramic VO2 Thin Films for Application to Smart Windows

Gao¹,

Kang²,

Chen³

et al. 2011

Nanofabrication

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“…To determine the phase-transition temperatures of the obtained films, hysteresis loops of pure and tungsten-doped VO 2 films were measured by recording transmittances and temperatures of these films at a fixed optical wavelength (2000 nm). As seen in Figure 10, a pure VO 2 film shows a hysteresis loop width of 31 °C at mean transmittance, which is much larger than that of pure VO 2 films on glass (11.1 ( 16) and 8 °C ( 7)) but is comparable to that of VO 2 -SiO 2 composite films (10,48). Hysteresis widening can be attributed to the states of grain boundaries (crystallographic misorientations and voids at boundaries, etc.)…”

Section: Tungsten Doping and Phase-transitionmentioning

confidence: 93%

A Novel Solution Process for the Synthesis of VO₂ Thin Films with Excellent Thermochromic Properties

Kang

Gao

Luo

2009

ACS Appl. Mater. Interfaces

160

111

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This article describes a novel and simple route to preparing VO(2) thermochromic films by using a VOCl(2) solution with poly(vinylpyrrolidone) (PVP). X-ray diffraction and Raman spectra showed that the VO(2) films deposited with PVP consisted of a nearly pure monoclinic/rutile (M/R) phase. Conversely, films prepared without PVP contained obviously impure crystalline phases. The as-prepared films with PVP showed excellent optical properties compared to those prepared by common gas-phase methods: an integral visible transmittance of 54.5% and an IR reduction (change in transmittance) of 41.5% at 2000 nm. The phase-transition temperatures were adjusted from 69 to 54 degrees C by tungsten doping. Equipment analyses revealed that PVP plays two roles in the film formation. First, it fundamentally acts as a film-forming promoter to improve physical gelation via interactions among oppositely charged carbonyl groups and amine groups of the polymer. Second, the negatively charged carbonyl groups can interact with VO(2+) to form a uniform mixed-gel film after solvent evaporation. Thus, the addition of PVP can stabilize the solution and improve the as-prepared film quality and phase purity. The current study suggests that the process has promise in applications of smart windows.

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Synthesis and optical properties of vanadium dioxide nanoparticles in nanoporous glasses

Cited by 10 publications

References 5 publications

Effects of Annealing Parameters on Optical Properties of Thermochromic VO₂ Films Prepared in Aqueous Solution

Effects of Annealing Parameters on Optical Properties of Thermochromic VO₂ Films Prepared in Aqueous Solution

Solution Processing of Nanoceramic VO2 Thin Films for Application to Smart Windows

A Novel Solution Process for the Synthesis of VO₂ Thin Films with Excellent Thermochromic Properties

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Synthesis and optical properties of vanadium dioxide nanoparticles in nanoporous glasses

Cited by 10 publications

References 5 publications

Effects of Annealing Parameters on Optical Properties of Thermochromic VO2 Films Prepared in Aqueous Solution

Effects of Annealing Parameters on Optical Properties of Thermochromic VO2 Films Prepared in Aqueous Solution

Solution Processing of Nanoceramic VO2 Thin Films for Application to Smart Windows

A Novel Solution Process for the Synthesis of VO2 Thin Films with Excellent Thermochromic Properties

Contact Info

Product

Resources

About

Effects of Annealing Parameters on Optical Properties of Thermochromic VO₂ Films Prepared in Aqueous Solution

Effects of Annealing Parameters on Optical Properties of Thermochromic VO₂ Films Prepared in Aqueous Solution

A Novel Solution Process for the Synthesis of VO₂ Thin Films with Excellent Thermochromic Properties