| Summary: | 碩士 === 國立交通大學 === 應用化學系所 === 93 === Anthracene-based blue host material, 2-methyl-9,10-di(2-naphthyl) anthracene (MADN) has a stable thin-film morphology. When doped with a highly fluorescent yield blue dopant, p-bis(p-N,N-diphenyl- aminostyryl)benzene (DSA-Ph), it achieved a highly efficient EL efficiency of 9.7 cd/A with a greenish-blue color of (0.16, 0.32) and a long operational lifetime of 46,000 h. But the color purity is still not adequate for full-color OLED display application. To develop deep blue dopants, the most straightforward solution is to shorten the conjugation length of DSA-Ph. Hence we synthesized (E)-4,4’-bis(N,N-diphenylamino)stilbene (SB-1)、(E)-4,4’-bis(carbazolyl)stilbene (SB-2)、(E)-4,4’-bis(9,9’-dimethylacridine) stilbene (SB-3) and (E)-4,4’-bis(2,2’-iminodibenzyl) stilbene (SB-4).
The SB-1 doped device achieved an EL efficiency of 3.1 cd/A with a deep blue CIE coordinates of (0.15, 0.16). But the SB-1 molecule would aggregate easily and the device had problems of color shift under high/low drive current density.
We modify the molecular structure of SB-1 to solve the problems and synthesized SK series compounds. The 4-N,N-diphenylamino-4’-[2-(4-N’,N’- diphenylamino-phenyl)–vinyl]biphenyl (SK-1) doped device achieved an high EL efficiency of 4.7 cd/A with a very saturate blue CIEx,y coordinates of (0.14, 0.13). The device performance under high/low drive current density is stable. Hence, the SK-1 can be employed as deep blue dopant of full color OLED technique.
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