| Summary: | 碩士 === 國立屏東科技大學 === 機械工程系所 === 98 === The ways how to increase the luminescence of organic electroluminescent devices (OLED) is an important topic. In this study, we will investigate the electrical and optical characteristics of the organic electroluminescent devices (OLED) with a double-buffer layer (DBL) of copper phthalocyanime (CuPc) and m-MTDATA between the NPB and ITO were fabricated by a vacuum evaporation method and thermal annealing.
ITO anodes suffered conditions of nitrogen rapid thermal annealing. The device performance is further enhanced after the as-deposited buffer layer film is thermally annealing, which is ascribed to lowering of the effective energy barrier height for hole injection and clearly reduces the roughness of the ITO surface.
Concerning to the study of the properties of CuPc and MTDATA, we observe the optimum optical characteristic with CuPc thickness of 10 nm and m-MTDATA thickness of 20 nm. Furthermore, The study of OLED with a CuPc layer with a thickness of 3.3nm matched to a m-MTDATA layer with a thickness of 6.7 nm were the most efficient. When 12.5 V is applied, the green luminescence is maximal, at 2530 cd/m2 and the Luminous efficiency was maximum at 3.3 cd/A when a current density of 50 mA/cm2 was applied.
The conclusion of this shows that the structure of thermal annealing on double buffer layer can be used to increasing Luminous efficiency by reducing excess hole injection.
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