Synthesis Of Organic Electrophosphore Scenct Polymers Materials And Study On Their Optoelectronic Properties

The development history, industrialization process and status of organ/polymer electroluminescent materials are reviewed in this dissertation. The research progress of organic electrophosphorescenct polymers is especially introduced. At present, organic small molecule phosphorescent devices have achieved efficient luminescence, but the maximum external quantum efficiency of these devices are mostly obtained in lower current density, and with the increase of the current density, the luminescent efficiency decreased. Meanwhile, there exists such problem as phase separation during the long period of service, which leads to life of devices down, and severely restricts its application in OLEDs/PLEDs. The electrophosphorescenct polymers which are prepared by connecting phosphorescent complex to the main chain or side chain of polymer have many advantages such as simple synthetic method, easy molecular design and adjustment of emitting light color, simple device process and good stability in high current density. So there is a very important application prospect on the designed and manufactured efficient white light-emitting polymers which is necessary to solid-state lighting and full-color display, but the efficiency of phosphorescent polymer devices is low. In response to above-mentioned problems, a series of organic electrophosphorescenct polymers were synthesised and their optoelectronic properties were studied: all the compounds synthesized were characterized by IR, NMR, and element analysis, and the photophysical property, thermal stability, electrochemical property and electroluminescent property of these polymers were also investigated by UV absorption spectra, fluorescence spectrum, thermogravimetric analysis, cyclic voltammetry and Instaspec 4 CCD spectrometer. The main contents of this paper are as follows:(1) By introducing phenylisoquinoline-based iridium complex to the side chain of polyfluorene, and oxadiazole unit with electronic transmission property, carbazole unit with hole-transporting property, benzene unit with good thermal stability and solubility property to the main chain of polyfluorene respectively, three kinds of new side chain phosphorescent conjugated polymers (PFOXDIrpiq, PFCzIrpiq, PFPhIrpiq) were designed and synthesized. The electroluminescent properties of these phosphorescent polymers were studied, and the effect of carrier transmission groups and the content of phosphorescent iridium complex on the photophysical, electrochemical and thermal stability properties of these polymers were investigated. When the mole content of phosphorescent iridium complex is 3%, the device with the configuration of ITO//PEDOT:PSS (50 nm)// PFOXDIrpiq0.03 (80 nm)//LiF (0.5 nm)/Al (150 nm) exhibited the maximum brightness of 1125 cd/m² and maximum current efficiency of 1.2 cd/A.(2) A kind of new phosphorescent polymer grafted with carbazole unit and oxadiazole unit on the side chain and end-capped with cyclometalated iridium complex on the main chain was designed and synthesized. The photophysical, thermal stability, electrochemical and electroluminescent property of the polymer which contains bipolar transmission function groups were investigated. With a configuration of ITO/PEDOT/PVK/Polymer/CsF/Al, a single layer device using C2 as luminescent layer shows a good performance, the device exhibited a turn-on voltage (Von) of 5.3 V, a maximum current efficiency of 0.48 cd/A and the the maximum brightness of 692 cd/m².(3) By introducing oxadiazole unit, carbazole unit and phosphorescent iridium complex to the side chain of polyfluorene, a class of new side chain phosphorescent conjugated polymers (P1-P4) which contain bipolar transmission function groups were designed and synthesized. The electroluminescent properties of these phosphorescent polymers were studied, and the effect of carrier transmission groups and the content of phosphorescent iridium complex on the photophysical, electrochemical and thermal stability properties of these polymers were investigated. When the mole content of phosphorescent iridium complex is 12.5 %, the device with the configuration of ITO/PEDOT (40 nm)/PVK (40 nm)/P4 (80 nm)/CsF (4 nm) /Al (120 nm) exhibited the maximum brightness of 3068 cd/m² and the maximum external quantum efficiency of 0.48 %, and the color coordinates CIE_x,y values (0.44, 0.52).