Research On ReO₃ Thin Film Applied To Multilayer Translucent Anode In OLED

Organic Light-Emitting Diode(OLED),as a popular organic optoelectronic device in recent years,has the advantages of low blue-ray damage,emitting natural and soft light,and using green materials.It is widely used in the field of electronic display and lighting.Especially in recent years,OLED displays have gradually surpassed liquid crystal displays,and OLED display technology has become the mainstream display technology.In OLED devices,translucent electrodes have a great influence on the performance of device.The performance of electrode mainly depends on the electrode structure and electrode materials.Therefore,exploring translucent electrode structures and electrode materials with better performance has become a research hotspot in OLED devices.Dielectric/Metal/Dielectric(DMD)translucent electrodes with multilayer structure have outstanding performance in optical,electrical and flexible aspects.A wide range of metals and dielectrics can be selected in DMD electrodes.In this paper,DMD electrode with multilayer structure is chosed as an anode in OLED device.In addition,there are few detailed studies on the performance of OLED devices with transition metal oxide of rhenium trioxide(ReO₃).Therefore,this thesis focuses on the research of DMD anode with ReO₃and its influence on the performance of OLED device.The researching work includes the following parts:(1)Determination of ReO₃ film preparation parameters.Exploring the preparation process of ReO₃ film by using an optical microscope to observe ReO₃ film.It was found that ReO₃ molecules are extremely sensitive to water molecules and oxygen molecules.ReO₃ films are easy to absorb water.When exposed in the atmosphere,the ReO₃ films will be destroyed.The final deposition parameters of ReO₃ film were determined as follows:ReO3 must be fully degassed when vacuum thermal evaporation is used to prepare the film.The degassing process is:slowly increasing the temperature until the evaporation rate of the material is 0.01(?)/s.At this time,reducing the evaporation temperature by 40°C,and maintaining the temperature for two hours to complete the degassing process.The evaporation rate of ReO₃ film is 0.2(?)/s,and the evaporation source temperature is about 430?;(2)Electron injection layer material matching.Comparing the OLED devices with Li F and Liq as electron injection layer,it is determined that Li F is used as the electron injection material in the device;(3)Two transition metal oxides of molybdenum trioxide(MoO₃)and rhenium trioxide(ReO₃)are used in MoO₃/Al/ReO₃ translucent anodes.the device with structure of MoO₃(20 nm)/Al(8 nm)/ReO₃(X=10,15,20 nm)/NPB(45 nm)/Alq₃(60 nm)/Li F(1 nm)/Al(100 nm)is used to optimize the thickness of ReO₃.The optical and electrical properties of OLED device were tested.The optimal thickness of ReO₃ film is 15 nm for the best OLED electrical properties.The current density is up to 497 m A?cm²,the luminance is up to 161cd?m²,the value of current efficiency and power efficiency are less than 1.MoO₃/Al/ReO₃ translucent anodes are used in OLED devices,and the performance of device is not good.The reasons should be:carrier injection is unbalanced in the device;Al/ReO₃interface reaction has an effect on the work function of anode;ReO₃ needs to be doped with other materials.