1,721,384 research outputs found
Templated Growth of Smart Coatings: Hybrid Chemical Vapour Deposition of Vanadyl Acetylacetonate with Tetraoctyl Ammonium Bromide
No full textHybrid aerosol assisted and atmospheric pressure chemical vapour deposition methodology has been utilised to produce thin films of vanadium dioxide from vanadyl acetylacetonate. Tetraoctyl ammonium
bromide (TOAB) was used in the aerosol precursor solution. The films were analysed by X-ray diffraction, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy. Their optical and thermochromic behaviour was also determined. It was found that the use of TOAB had a templating effect that led to a halving in the particle size and that this consequently led to a significant decrease in the thermochromic transition temperature of the films to 34 8C
Hybrid Chemical Vapour Deposition: Gold and Vanadium Dioxide Nano-composites for Smart Windows
No full textFunctional Thin Films for Glazing Application
No full textVanadium dioxide is a thermochromic material with great potential for use in intelligent glazing. The thermochromic properties result from a metal to semiconductor transition (MST) where there is an associated structural change from the higher temperature rutile structure to the lower temperature monoclinic structure. This structural transition results in significant changes in optical properties and electrical conductivity. Various chemical vapour deposition (CVD) methodologies have been utilised, to produce thin films of vanadium dioxide. Different strategies are presented for the inclusion of metal dopants and the production of nano-composites. The use of a surfactant molecule, tetraoctyl ammonium bromide (TOAB), is discussed and shown to significantly alter the morphology and microstructure of the deposited films. It is further shown that these microstructural changes lead to an enhancement of thermochromic properties. Films were analysed by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Their optical and thermochromic behaviour was also determined. The effect of transition metal dopants leads to changes in the MST temperature; furthermore incorporation of gold nano-particles in the films leads to significant changes in the colour of the film due to the presence of a surface plasmon resonance band. Energy modelling studies were performed with data generated from these coatings and several standard glazing products to illucidate their usefulness in contemporary archetecture. It was found that transition temperature, colour and the thermochromic “switching” properties all play a part in the energy performance of these coatings
Energy modelling studies of thermochromic glazing
No full textTheoretically thermochromic glazing has the potential to reduce energy consumption in buildings by
allowing visible light for day lighting, reducing unwanted solar gain during the cooling season, whilst
allowing useful solar gain in the heating season. In this study building simulation is used to predict the
savings made by novel thermochromic glazing coatings compared to standard products, for locations
with different climates. The results suggest that thermochromic glazing can have a significant energy
saving effect compared to current approaches
Nano-composite thermochromic thin films and their application in Energy-efficient glazing
No full textA hybridatmosphericpressureandaerosol-assistedchemicalvapourdepositionstrategyispresentedas
a facileroutefortheproductionofvanadiumdioxidenano-compositethinfilms.Theeffectofthe
inclusionofgoldnanoparticlesandtheuseofasurfactantmolecule,tetraoctylammoniumbromide,is
discussed.Thefilmswerefullycharacterisedusingawidevarietyoftechniques,includingscanning
electronmicroscopy,X-raydiffraction,X-rayphotoelectronspectroscopyandUV/vis/NIRspectroscopy.
It isshownthatmicro-structuralchangesbroughtaboutbycarefulcontroloffilmgrowthconditions,
and/ortheuseofsurfactant,leadtoanenhancementofthermochromicproperties.Goldnanoparticle
incorporationleadstoasignificantchangeinthecolourofthefilmsfromayellow-browncolourtoa
varietyofgreensandbluesdependingonthegoldnanoparticleconcentration.Thefilmsbecomemore
reflectiveintheinfra-redwithincreasedgoldnanoparticleincorporation.Opticaldataareusedin
energy modellingstudiestoelucidatethefilmpotentialasanenergy-savingcoatinginarchitectural
glazing.Theenergymodellingresultssuggestthatforwarmerclimatesthethermochromicnano-
compositesinvestigatedhereleadtosignificantenergysavingswhencomparedwithplainglassand
other standardindustryproducts
Hybrid Aerosol Assisted Atmospheric Pressure Chemical Vapour Deposition: A Facile Route Toward Nano-Composite Thin Films?
No full textA hybrid chemical vapour deposition strategy is presented as a facile route for the production of vanadium dioxide nano-composite thin films. The effect of the inclusion of gold nano-particles and the use of a surfactant molecule; tetraoctylammonium bromide (TOAB), is discussed. The films are fully characterised and it is shown that micro-structural changes lead to an enhancement of thermochromic properties, whilst gold nano-particles lead to a change in the films optical properties. Optical data is used in building energy simulation studies to elucidate the films potential as an energy saving coating for architectural glazing
Energy modelling studies of enhanced glazing
No full textThe research on new “energy materials” is a very interesting field of study in the direction of energy saving control in the building construction sector. Lots of studies have been carrying on to develop new enhanced glazing, new synthesis and analysing procedures but simulating their real behaviour is often very difficult and expensive. The easiest way to test the energy performance of new enhanced glazing, in this work doped vanadium (IV) dioxide thermochromic glazing, is to simulate the way they would respond if they were installed in a building. The software used to perform such simulations is Energy PlusTM which is an energy analysis and thermal load simulation program. The aim of this study is understanding how efficient thermochromic coating could be if applied in several climate conditions at different latitudes in the northern hemisphere and in different kind of buildings in comparison to some products that are still in the market
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Optimisation of Thermochromic Thin Films on Glass; Design of Intelligent Windows
No full textTheoretically thermochromic glazing has the potential to reduce energy consumption in
buildings by allowing visible light for day lighting, reducing unwanted solar gain during the cooling
season, while allowing useful solar gain in the heating season. In this study building simulation is
used to predict the savings made by novel thermochromic glazing coatings compared to standard
products, for locations with different climates. The results suggest that thermochromic glazing can
have a significant energy saving effect compared to current approaches
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