ThermochromicVO2thinfilmforsmartwindowY.J.Zhou

Y.C.ZhouT.Y.ZhouJ.Q.zhenggroup21Tableofcontents1Introduction2Methodsofsynthesis3Problems&SolutionsWinterSummerTooutsideFromoutsideWindow58%Window73%Floor7%Floor3%Roof5%Roof11%Wall15%Ventilation15%Wall7%Ventilation6%Twoquestions！

Workingprinciple

VO2undergoesreversibletransitionatcriticaltemperatureTc(68℃);below68℃，VO2issemiconductingandrelativelyinfraredtransparent,andaboveTcitismetallicandinfraredreflecting.(NIR:0.78-2.5um)

ResistanceofasuspendedVO2nanobeammeasuredinafour-probegeometryasafunctionoftemperature[1][1]JinqianWu,QianGu,Nanoletter,2006Vol.6,No.10,2313-2317.[2]LitaoKang,?,?YanfengGao,ACS,Appliedmaterial&interfaces,VOL.1?NO.10?2211–2218?2009OpticaltransmittancespectraofVO2film[2]Methodsofsynthesis

Sol-gelmethod

ChemicalvapordepositionDC、RF&magnetronsputteringPluselaserdeposition★★Sol-gelmethodMixingsolution(HCl,N2H4,V2O5)Sol(OnlyVOCl2)GelAdding

PVPAdjustpHPrimaryproductSpin

coating[5]LitaoKang,YanfengGao,J.Phys.Chem.C,2010,114,1901-1911Secondproduct

Drying

FinalproductAnnealingWithoutPVPPVPMeritsofSol-gelmethodLowcostSol-gelEasy

handlingEasefor

dopingLargescale

processVaporizationandTransportofPrecursorMoleculesintoReactorAdsorptionofPrecursorMoleculestoSurfaceDecompositionofPrecursorMoleculesonSurfaceandIncorporationintoSolidFilmsRecombinationofMolecularByproductsandDesorptionintoGasPhase

ChemicalvapordepositionDiffusionofPrecursorMoleculestoSurface

UniformityRepeativityLargescaleFilmthicknesscontrolGoodsubstrateadhesionCVDProblemsApplications???Q1:HighMIPTtemperature(≈68℃)Q2:Lowvisibletransmittance(<50%)Q3:WeakopticalcontrastintheIRregionQ4:Unfavorablecolor&Immatureprocessing

Godisimpartial,whoendowsakindofmaterialwitho