| Summary: | 碩士 === 國立屏東科技大學 === 機械工程系所 === 98 === In this study, we used host guest emitter system to increase efficiency of organic electroluminescent devices, and studied the effects for the electrical and optical characteristics. We fabricated multilayer structures by vacuum evaporation method : ITO/ m-MTDATA/ NPB/ Alq3/ LiF/ Al, and then doped fluorescent dye into hole transport and electron transport materials. The emission spectrum of the devices was red-shift, and the luminescence was enhanced by the energy transfer between host to guest. The optimum doping concentration of NPB and Alq3 was 5wt% and 3wt%. The theory of quantum well was applied to change the doping method. Due to this structure would increase the recombination probability. It showed the performance of the devices was significantly improved with the thickness of each layer in the emitting layer was 1.5nm after an experiment. It had a best result with Alq3 being a host. When 14.9V is applied, the luminescence is maximal, at 7050 cd/m2 and the Luminous efficiency is maximal at 4.5cd/A when a current density of 20 mA/cm2 is applied.
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