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1、LightEmittingDiodes(LED)Whatislight?Electromagneticspectrumororc=299,792,458 m/sPhotopic(black)andscotopic(green)luminosityfunctions.ThephotopicincludestheCIE1931standard(solid),theJudd-Vos1978modifieddata(dashed),andtheSharpe,Stockman,Jagla&Jägle2005data(dotted).Thehorizontalaxisiswavel
2、engthinnm.VisibleLightandColorThefollowingequationcalculatesthetotalluminousfluxinasourceoflight.1,luminousenergyistheperceivedenergyoflight.Thisissometimesalsocalledthequantityoflight.2,luminousintensityisameasureofthewavelength-weightedpoweremittedbyalightsourceinaparticulardirectionpe
3、runitsolidangle,basedontheluminosityfunction,astandardizedmodelofthesensitivityofthehumaneye.Whatiscolorandhowisitdetermined?CIE1931XYZColorMatchingFunctionsHowcanwecontrolthecolor?PixelsfordisplaysHowdoesamaterialemitlight?Interactionbetweenlightandmaterial:ElectronicbanddiagramPhotolum
4、inescence(PL)Electroluminescence(EL)Eg=hvEg=hvEpPLPLIfamaterialcanproducelightemissionwhichcanbevisible,itmustbe:1,Theenergywidthofthebandgapislocatedatvisiblezone2,Theexcitons(electronandholepairs)havebondenergy3,Theexcitonshaveenoughlifetime无机发光二极管OnewaytoconstuctanLEDistodepositthrees
5、emi-conductorlayersonasubstrate.Betweenp-typeandn-typesemiconductorlayers,anactiveregionemitslightwhenanelectronandholerecombine.Consideringthep-ncombinationtobeadiode,thenwhenthediodeisforwardbiased,holesfromthep-typematerialandelectronsfromthen-typematerialarebothdrivenintotheactivereg
6、ion.Thelightisproducedbyasolidstateprocesscalledelectroluminescence.InorganicLEDStructureStructureLight-emittingProcessI-VCurveI-L-CurveWhiteLEDlightbulbRGB-LEDsRed-YellowGreen-BlueLEDspectraWhiteLEDspectraOrganicandPolymerMaterialsinElectronics有关有机和高分子材料的问题存在两类不同的有机材料，theyarepolymermate
7、rialsandmolecularmaterials.Suchas：OrganicLED有机发光二极管Whyaresomeorganic/polymermaterialssemiconductiveandgoodforlight-emissionMaterials:C-C=C-CSP2hybridizationTheenergyleveldifferenceofπ(bonding)——π*(antibonding)iswithintherankofvisiblelight.Tobealight-emittingorganicfilm,th
