简介:(Y,Gd)BxV1-xO4-x:Eu3+phosphorswerepreparedbysolidstatereaction.Theredemissioncolorpurityof(Y,Gd)BxV1-xO4-x:Eu3+phosphorismuchbetterthanthatoftherecentwidely-usedcommercialredemittingphosphor(Y,Gd)BO3:Eu3+anditsrelativeemissionintensityis84%ofthecommercialphosphor(Y,Gd)BO3:Eu3+.Itisexpectedthat(Y,Gd)BxV1-xO4:Eu3+phosphorwillbeapromisingcandidateforPDP(plasmadisplaypanels)application.
简介:以硝酸锶、七钼酸铵、氧化镨为原料,采用低温燃烧法合成白光发光二极管(whitelightemittingdiode,简称WLED),用新型红色荧光粉SrMoO4:Pr3+,并研究其光谱性质。结果表明,SrMoO4:Pr3+激发光谱中Pr3+在449nm处有一最强3H4->3P0激发峰,其激发范围与蓝光LED芯片相匹配,能被蓝光有效激发;发射光谱在644nm处有最强峰,属于Pr3+的3P0->3F2跃迁,发红光,说明SrMoO4:Pr3+荧光粉是1种潜在的白光LED用蓝光激发的红色荧光粉。同时还研究了燃烧温度、尿素用量、稀土Pr3+掺杂量对荧光粉发光强度的影响,得出制备SrMoO4:Pr3+的最佳条件为:燃烧温度600℃,尿素用量为理论尿素用量的3倍,稀土Pr3+离子掺杂摩尔分数为2%。
简介:ThereactionofNdCl3withlithiummethylnaphthalenein1:2moleratioinTHFgeneratesblackpowder.Thepowderreactswithcyclooctatetraene(COT)inTHFtoformthetitlecomplex.[Li(THF)4Nd(C8H8)2]·2THFcrystallizesinthemonoclinicspacegroupP2/cwithunit-celldimensionsa=1.7858(7)nm,h=1.3243(4)nm,c=1.8086(6)nm.β=106.52(4)°,V=4.10nm3andDc=1.268g/cm3forZ=4.F(000)=1660,R=0.0774,Rn=0.0733.Thecomplexconsistsofdiscreteion-pairandtwoTHFmoleculesadduct.Intheanion,theneodymiumatomiscoordinatedbytwoCOTrings.ThestructureofthecationshowsthatthelithiumatomisattachedwithTHFmoleculesonly.
简介:Tobreakthroughthebottle-neckofquantumyieldinupconversion(UC)core-shellsystem,weelucidatedthattheenergytransferefficiencyincore-shellsystemhadanevidentcontributionfromthechargetransferofinterfacewithrelatedtotwofactors:(1)bandoffsetsand(2)bindingenergyareadensity.Thesetwovariablesweredeterminedbymaterialintrinsicpropertiesandcore-shellthicknessratio.Wefurtherunraveledthemechanismofnon-radiativeenergytransferbychargetransferinduceddipoleattheinterface,basedonaquasi-classicalderivationfromF?rstertyperesonantenergytransfer(FRET)model.Withstablebondingacrosstheinterface,thecontributionsonenergytransferinbothradiativeandnon-radiativeenergytransfershouldalsobeaccountedtogetherinAuzel'senergytransfer(ETU)modelincore-shellsystem.Basedonthediscussionaboutinterfacebonding,bandoffsets,andformationenergies,wefiguredoutthesignificanceofinterfacebondinginducedgapstates(IBIGS)thatplayedasignificantroleforinfluencingthechargetransferandradiativetypeenergytransfer.Theinterfacebandoffsetswereakeyfactorindominatingthenon-radiativeenergytransfer,whichwasalsocorrelatedtocore-shellthicknessratio.Wefoundthattheenergyareadensitywithrelatedtocore/shellthicknessratiofollowedthetrendofBoltzmansigmoidalgrowthfunction.Bythephysicaltrend,thisworkcontributedareferencehowthemulti-layeredcore-shellstructurewasformedstartingfromtheverybeginningwithinminimumsize.Aroutewaspavedtowardsasystematicstudyoftheinterfacetounveiltheenergytransfermechanismincore-shellsystems.
简介:采用包埋-刷涂法在C/C复合材料表面制备SiC/ZrSiO4复合涂层,借助X射线衍射(XRD)、扫描电镜(SEM)和能谱分析(EDS)等测试手段分析该复合涂层的微观结构,并研究SiC单涂层和SiC/ZrSiO4复合涂层在1500℃静态空气中的抗氧化性能。结果表明:包埋法制备的SiC内涂层结构疏松,具有较好的抗氧化性能,氧化55h后质量损失率仅为0.5%,但氧化58h后,涂层内部形成大孔洞并产生贯穿孔隙,导致涂层失效,质量损失率迅速增加到2.1%。SiC/ZrSiO4复合涂层由非均质镶嵌式结构的ZrSiO4涂层紧密覆盖在SiC内涂层表面而成,具有优异的抗氧化性能,氧化198h后质量仅增加0.5%,并且基本不再随时间延长而增加;复合涂层不仅能自愈合外涂层的缺陷和裂纹,还能抑制氧化过程中大孔洞的形成,避免贯通孔隙的产生。
简介:以六水合氯化钴(CoCl2·6H2O)和水合三氯化钌(RuCl3·3H2O)为前驱体,采用胶体法制备超级电容器用(RuO2/Co3O4)·nH2O复合薄膜电极材料。用X射线衍射仪以及CHl660C电化学工作站对该复合薄膜的物相结构及电化学性能进行表征。结果表明:当COCl2'6H20和RuCl3·3H2O的物质的量比n(Co):n(Ru)为2:1时,于350℃下热处理2.5h制备的复合薄膜电极具有优良的性能,在浓度为0.5mol/L的H2S04电解液中其比电容达到512F/g,500次充放电循环后比电容量保持在充放电循环前的96.1%;充放电电流为0.01A时,内阻为1.2Ω。
简介:Thesynthesis,compositionoptimization,VUVPhotoluminescence(PL)spectra,andopticalproperties,of(Y,Gd)(V,P)O4∶Eu3+phosphorswereinvestigatedbysynchrotronradiation.TheVUVPLEspectraandthecorrelationamongVUVPLintensity,λem,andEu3+,Gd3+,andP-contentwereestablished.ThePLEspectralstudiesshowedthat(Y,Gd)(V,P)O4∶Eu3+exhibitedsignificantabsorptionintheVUVrange.TheVUVPLintensitywasfoundtoenhancewithPO43-andGd3+-doping.Furthermore,thechromaticitycharacteristicsof(Y,Gd)(V,P)O4∶Eu3+werealsofoundtobe(0.6614,0.3286)andcomparedagainst(Y,Gd)BO3∶Eu3+asareference.Basedonthecharacterizationresults,wearecurrentlyimprovingandevaluatingthepotentialapplicationof(Y,Gd)(V,P)O4∶Eu3+asanewred-emittingPDPphosphor.
简介:Whitelight-emittingYVO_4:1mol.%Dy~(3+),xmol.%Eu~(3+)phosphorpowderswithordermorphologyandwellcrystallizationwerehydrothermallysynthesizedat180°C.Themicrostructure,white-lightemission,andlight-emittingmechanismofthepowderswerecarefullystudiedusingX-raydiffractometry,scanningelectronmicroscopyandphotoluminescencespectra.TheexcitationandemissionspectraofthephosphorpowdersindicatedthecoexistenceofefficientenergytransferfromEu~(3+)toDy~(3+)andinefficientenergytransferfromDy~(3+)toEu~(3+)besidestheenergytransferfromVO_4~(3–)toEu~(3+).IncreasingtheEu~(~(3+))concentrationinitiallyenhancedandthenweakenedtheluminescentintensityofDy~(3+).Thewhite-lightemissionsofYVO_4:1mol.%Dy~(3+),xmol.%Eu~(3+)phosphorpowderswerebothrelatedtotheenergytransferbetweenVO_4~(3–)andDy~(3+)/Eu~(3+),aswellasbetweenEu~(3+)andDy~(3+).TheinefficientenergytransferfromDy~(3+)toEu~(3+)wasfirstfound.