| 초록 |
A series of carbazole core and arylamine building blocks based smaller molecular hole transporting materials namely, 7a, 7b and 7c were designed and synthesized by using Buchwald-Hartwig amination reaction with higher yields over 66 %. HTMs 7a and 7b showed stable decomposition temperatures of 400 and 380 ºC without any crystalline features and also revealed good solubility in most of the organic solvents. Among the designed HTMs, HTM 7a and HTM 7b were showed similar HOMO energy levels (5.14 eV) while HTM 7c was noticed with higher HOMO level of 5.06 eV. When we fabricated red phosphorescence based device, HTM 7a was exhibited identical device performance with NPB based reference device. The current and power efficiencies were 28.2 cd/A and 26.5 lm/W for HTM 7a based device, which was higher than that of HTM 7b and 7c in the same study. HTM 7c showed poor device characteristics due to its higher hole injection barrier (0.44 eV). |
