| 초록 |
High efficiency phosphorescent white organic light emitting diodes were developed by managing the charge transport properties of the host materials. 4,4’,4”-tris(N-carbazolyl)triphenylamine(TCTA), 1,3,5-tris(N-phenylbenzimidazole-2yl)benzene(TPBi) and mixed host of TCTA and TPBi were used as a red and green host materials. Hole and electron injection could be controlled by the change of the host structures of red and green emitting layers in R/B/G stacked device. A high quantum efficiency of 13% was obtained at a luminance of 1000 cd/m2 and there are little efficiency roll off between 100 cd/m2 to 10000 cd/m2. |
