| Summary: | 碩士 === 國立東華大學 === 材料科學與工程學系 === 99 === In this paper, we used the new derivative of 3-(4’-tert-butylphenyl) -4-phenyl-5-(4”-biphenyl)-1,2,4-triazole (TAZ)—TAZ-B and TAZ-C to produce high efficiency blue organic light emitting diodes.
In studying of TAZ-B materials, we found that it have lower HOMO level, so it can be used in hole blocking layer. By using appropriate device structure, the highest current efficiency, power efficiency and EQE were reached to 37.9 cd/A, 23.8 lm/W and10.5%, respectively.
Investigating into TAZ-C materials, it can use as the host because of 4.07 eV bandgap and 3.09 eV triplet energy. The device were fabricated with FIrpic dopanting in TAZ-C host, and electron transporting TAZ layer, so the superior device performance with high current, power efficiencies and EQE of 44.2 cd/A, 27.8 lm/w, and 15.7%, respectively. Then, we used mixed layer and double emitting layer to reduce the driving voltage and promote the efficiency. The use of mixed host with excellent device resulted in a current efficiency of 39.9 cd/A, a power efficiency of 38.7 lm/W and a high EQE of 16.6%. And the use of double emitting layer with excellent device resulted in a current efficiency of 45.4 cd/A, a power efficiency of 37.8 lm/W and a high EQE of 15.7%.
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