The Study On Electroluminescence Performance And Electroluminescence Mechanism Of Porphyrin Doped Organic Light-emitting Devices

Organic electroluminescent devices as well as organic light-emitted diode, have attracted particular attention because of their potential applications in efficient, low -voltage, easy-fabrication, and full-color flat panel displays. Doping is a good way to realize the full-color display for OLED. Doped style OLED can avoid the organic material's concentration quench phenomenon in high concentration, and in the same time, the host material's merit for good "form film" character and good charge transport characters can be utilized. For different doped OLED, their electroluminescence mechanism is different, some doped device's electroluminescence is domain by energy transfer(ET) mechanism while other's is by the charge trapping(CT) mechanism. To understand the doped OLED's mechanism can give some useful guidance for design more efficient device. This thesis is aimed to study the porphyrin doped OLED's electroluminescence mechanism. In summary, this thesis can be divided into four sections: At first, we simply introduced developing history, the luminescent mechanism, the structure and the fabrication of organic electroluminescent devices. And we summarized research advances on red electroluminescent devices and porphyrins in the luminescent field. Then, some different meso-substituted porphyrin compounds were prepared. The structure of all these compounds were testified by UV-Vis,MS and NMR .And then, we analyze the UV-Vis and fluorescence spectra of all the synthesized porphyrins and give a reasonable explain for their spectral difference. In section two, we designed the technology of fabricating doped organic electroluminescent devices according to the existing vacuum film-plating machine and introduce how to measure the OLED's electroluminescence characterics. In the third section, we introduce the method to measure the organic material's energy band structure by cyclic voltammetry method, and then measure the different meso-substituted porphyrin's energy band structure by this method. At last, the luminescence characterics and luminescence mechanism of devices by doping porphyrin into Alq3 was discussed. by analyzing the difference of porphyrin doped film's photoluminescence and the doped OLED's electroluminescence and the different structure's device's characterics, we can conclude the porphyrin doped OLED's mechanism is domained by charge trapping mechanism. And then, used this conclusion, design hole transport material co-doping's device which show more efficient electroluminescence performance.