Recent progress in VO2 smart coatings: Strategies to improve the thermochromic properties

Wang, Shufen; Liu, Minsu; Kong, Ling Bing; Long, Yi; Jiang, Xuchuan; Yu, Aibing

doi:10.1016/j.pmatsci.2016.03.001

Cited by 278 publications

(157 citation statements)

References 185 publications

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“…This type of variation in T(λ,τ) clearly is the desired one, and a glazing with a VO 2 -based TC thin film transmits more energy below τ c than above τ c . Similar properties have been recorded many times [31][32][33][34][35][36][37][38][39][40][52][53][54]. Figure 3 also demonstrates that corresponding data on R(λ) increase monotonically towards long wavelengths for the metallic-like state above τ c , which is the expected behavior.…”

Section: Basic Properties Of Vanadium Dioxide Thin Films and Nanopartsupporting

confidence: 80%

Thermochromic Oxide-Based Thin Films and Nanoparticle Composites for Energy-Efficient Glazings

Granqvist

Niklasson

2016

Buildings

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Today's advances in materials science and technology can lead to better buildings with improved energy efficiency and indoor conditions. Particular attention should be directed towards windows and glass facades-jointly known as "glazings"-since current practices often lead to huge energy expenditures related to excessive inflow or outflow of energy which need to be balanced by energy-intensive cooling or heating. This review article outlines recent progress in thermochromics, i.e., it deals with materials whose optical properties are strongly dependent on temperature. In particular, we discuss oxide-based thin surface coatings (thin films) and nanoparticle composites which can be deposited onto glass and are able to regulate the throughput of solar energy while the luminous (visible) properties remain more or less unaltered. Another implementation embodies lamination materials incorporating thermochromic (TC) nanoparticles. The thin films and nanocomposites are based on vanadium dioxide (VO 2 ), which is able to change its properties within a narrow temperature range in the vicinity of room temperature and either reflects or absorbs infrared light at elevated temperatures, whereas the reflectance or absorptance is much smaller at lower temperatures. The review outlines the state of the art for these thin films and nanocomposites with particular attention to recent developments that have taken place in laboratories worldwide. Specifically, we first set the scene by discussing environmental challenges and their relationship with TC glazings. Then enters VO 2 and we present its key properties in thin-film form and as nanoparticles. The next part of the article gives perspectives on the manufacturing of these films and particles. We point out that the properties of pure VO 2 may not be fully adequate for buildings and we elaborate how additives, antireflection layers, nanostructuring and protective over-coatings can be employed to yield improved performance and durability that make TC glazings of considerable interest for building-related applications. Finally, we briefly describe recent developments towards TC light scattering and draw some final conclusions.

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Section: Basic Properties Of Vanadium Dioxide Thin Films and Nanopartsupporting

confidence: 80%

Thermochromic Oxide-Based Thin Films and Nanoparticle Composites for Energy-Efficient Glazings

Granqvist

Niklasson

2016

Buildings

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“…As discussed earlier, pure or undoped VO 2 will show reversible or smart transition temperature at 68 °C32. However, the reduction of transition temperature (i.e., close to room temperature) is always beneficiary from the application point of view.…”

Section: Resultsmentioning

confidence: 94%

“…In general, the introduction of Mo or oxides of Mo are reported to have assisted in various extents of reduction in the transition temperature of VO 2 e.g., from about 68 °C32 to 55–30 °C1724, 50 °C25, 53–(−)91 °C15, 47.5–24 °C14 and 25 °C19. The optical properties such as transmittance15162122232425, reflectance14 and electrical conductivity of these coatings are also extensively studied14151820212223.…”

mentioning

confidence: 99%

Nanocolumnar Crystalline Vanadium Oxide-Molybdenum Oxide Antireflective Smart Thin Films with Superior Nanomechanical Properties

Dey

Nayak

Akinlabi

et al. 2016

Sci Rep

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Vanadium oxide-molybdenum oxide (VO-MO) thin (21-475 nm) films were grown on quartz and silicon substrates by pulsed RF magnetron sputtering technique by altering the RF power from 100 to 600 W. Crystalline VO-MO thin films showed the mixed phases of vanadium oxides e.g., V 2 O 5 , V 2 O 3 and VO 2 along with MoO 3 . Reversible or smart transition was found to occur just above the room temperature i.e., at ~45-50 °C. The VO-MO films deposited on quartz showed a gradual decrease in transmittance with increase in film thickness. But, the VO-MO films on silicon exhibited reflectance that was significantly lower than that of the substrate. Further, the effect of low temperature (i.e., 100 °C) vacuum (10 −5 mbar) annealing on optical properties e.g., solar absorptance, transmittance and reflectance as well as the optical constants e.g., optical band gap, refractive index and extinction coefficient were studied. Sheet resistance, oxidation state and nanomechanical properties e.g., nanohardness and elastic modulus of the VO-MO thin films were also investigated in as-deposited condition as well as after the vacuum annealing treatment. Finally, the combination of the nanoindentation technique and the finite element modeling (FEM) was employed to investigate yield stress and von Mises stress distribution of the VO-MO thin films.Vanadium oxides based films and coatings are extensively studied due to both thermochromic 14,15,[17][18][19][20]24,25,31 . The Mo and/or molybdenum oxide doped vanadium oxides are reported to be grown by a multitude of techniques such as magnetron sputtering technique 15 , atmospheric pressure chemical vapour deposition 26 , cathodic

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“…The use of bioinspired structures, such as moth eye type structures, has demonstrated that visible light transmittance can be dramatically increased to in excess of 75% whilst retaining reasonable thermochromic performance [205,206]. There has been further work in the area of nanothermochromics and the use of nanoparticle systems.…”

Section: Recent Advances In Thermochromic Glazingmentioning

confidence: 99%

Thin Films for Advanced Glazing Applications

et al. 2016

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Functional thin films provide many opportunities for advanced glazing systems. This can be achieved by adding additional functionalities such as self-cleaning or power generation, or alternately by providing energy demand reduction through the management or modulation of solar heat gain or blackbody radiation using spectrally selective films or chromogenic materials. Self-cleaning materials have been generating increasing interest for the past two decades. They may be based on hydrophobic or hydrophilic systems and are often inspired by nature, for example hydrophobic systems based on mimicking the lotus leaf. These materials help to maintain the aesthetic properties of the building, help to maintain a comfortable working environment and in the case of photocatalytic materials, may provide external pollutant remediation. Power generation through window coatings is a relatively new idea and is based around the use of semi-transparent solar cells as windows. In this fashion, energy can be generated whilst also absorbing some solar heat. There is also the possibility, in the case of dye sensitized solar cells, to tune the coloration of the window that provides unheralded external aesthetic possibilities. Materials and coatings for energy demand reduction is highly desirable in an increasingly energy intensive world. We discuss new developments with low emissivity coatings as the need to replace scarce indium becomes more apparent. We go on to discuss thermochromic systems based on vanadium dioxide films. Such systems are dynamic in nature and present a more sophisticated and potentially more beneficial approach to reducing energy demand than static systems such as low emissivity and solar control coatings. The ability to be able to tune some of the material parameters in order to optimize the film performance for a given climate provides exciting opportunities for future technologies. In this article, we review recent progress and challenges in these areas and provide a perspective for future trends and developments.

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Recent progress in VO2 smart coatings: Strategies to improve the thermochromic properties

Cited by 278 publications

References 185 publications

Thermochromic Oxide-Based Thin Films and Nanoparticle Composites for Energy-Efficient Glazings

Thermochromic Oxide-Based Thin Films and Nanoparticle Composites for Energy-Efficient Glazings

Nanocolumnar Crystalline Vanadium Oxide-Molybdenum Oxide Antireflective Smart Thin Films with Superior Nanomechanical Properties

Thin Films for Advanced Glazing Applications

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