The Interface Of Organic Light-Emitting Diodes And High Performance Blue Organic Light-emitting Diodes

The Organic Light-Emitting Devices(OLEDs) have developed for over 20 years. Its uniquecharacters such as light weight, thin, self-luminescence, fast response and flexible have attractedmany researchers'attention. The stability and efficiecy are still the two elements that block itsmassproduction.ThisthesismainlytalksaboutOrganicLight-EmittingDiodes,startingfromthelightingmechanismofOLEDs,studiedtheinterface'sinfluenceonthedeviceperformance.This thesis summarized the models of several interfaces. At the beginning, the inorganicsemiconductor theory is quoted in the organic semiconductors, such as the tunneling model, thebend-bandingtheory, and the interface dipoles. Particularly, some kinds of models are illustratedaccording to the interaction force of the interfaces. Though there's no specific model to explainall the interfaces, with the deeper investigation of the interface and the more advanced studymethods, the understanding of interface will be deeper. Commonly, one interface contains manyeffects.Theinterfacetheorywouldbemoresystematicinthenearfuture.Grapheneoxide(GO)thinfilmswereusedasainterfacemodifyinglayerbothintheOLEDsand Polymer Light-Emitting Devices (PLEDs). The good performance of poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) based PLED with GOthin films as the hole transport (HTLs) and electron blocking layer (EBLs) indicates that suchcheap and easily prepared GO is expected to be used as anode modifying material alternative topoly(3,4-ethylenedioxythiophene)(PEDOT):poly(styrenesulfonate)(PSS)inPLEDs.However,the GO film as a HTLlayer is bad for the device performance in OLEDs. This may because ofthe mobility in different meterials. The mobility of small molecular is much higher than thepolymer and GO. Therefore, the effect of GO as HTL in PLED is more obvious than that inOLEDs.A dumbbell-shaped SAH has been used as the bule-emitting material. DSFXPy-basednondoped OLEDs with a structure of ITO/MoO_x(2 nm)/m-MTDATA(20 nm)/NPB(10nm)/SFX-Py-SFX(30 nm)/TPBi(40 nm)/LiF(1 nm)/Al exhibit a maximum CE of 7.4 cd/A(4.6%at 260 cd m^-2) and excellent CIE coordinate (0.16, 0.15) (at 6500 cd m^-2), surpassing mostreported non-doped deep-blue OLEDs. Voltage-independent deep-blue CIE coordinate (0.17,0.17±0.01) with a maximum CE of 5.5 cd/A have been achieved in a simplified three-layer structure.