| Summary: | 碩士 === 國立臺灣師範大學 === 化學系 === 98 === Abstract
A series of materials derived from 3,7-disubstituted dibenzothiophene- S,S-dioxide for electroluminescent devices have been synthesized by Stille coupling, Buchwald-Hartwig coupling, and Suzuki coupling reactions. The fluorescence colors of these compounds can be tuned from blue to orange-red. These dibenzothiophene derivatives show good thermal stabilities: the glass transition temperatures (Tg) range from 112 to 207 ℃ and high thermal decomposition temperature range from 299 to 505 ℃. Compare to 2,8-disubstituted congeners of dibenzothiophene- S,S-dioxide, the two substituents in these compounds have better electronic communication. Three types of electroluminescent devices were fabricated by using vacuum deposition: ITO/cpd/TPBI/LiF/Al (device I), ITO/NPB/cpd/LiF/Al (device II) and ITO/cpd/LiF/Al (device III), where these compounds (cpd = SOO-1, SOO-2, SOO-3, SOO-4, SOO-8) were used as the hole-transporting and emitting layer, electron-transporting and emitting layer, and electron- and hole-transporting as well as emitting layer, respectively. The performance of device II and device III based on SOO-3 is promising: device II has the maximum efficiency and the maximum luminescence of 3.09% and 20681 cd/m2, respectively, and the external quantum efficiency (ext) of 2.05% at a current density of 100 mA/cm2; the maximum efficiency and the maximum luminescence reach 1.69% and 15717 cd/m2, respectively, for device III. The ext also reaches 1.29% at a current density of 100mA/cm2. Spin-coating technique was used to fabricate the device ITO/PEDOT:PSS/PVK + cpd (20 wt%)/BCP (10 nm)/TPBI (40nm)/LiF (1 nm)/Al (120 nm), where cpd represents SOO-5, SOO-6 or SOO-7. Among these, SOO-6 shows the best performance: the maximum external quantum efficiency of 3.42% and the maximum luminescence of 8063 cd/m2; at the current density of 100mA/cm2, ext is as high as 1.16%. Device of configuration, ITO/ployfluorene + cpd (20 wt. %)/TPBI/ LiF/Al (cpd = SOO-9 or SOO-10), were also fabricated. The device of SOO-10 emits pure white light due to incomplete energy transfer, and the CIE coordination is at (0.35, 0.33).
|
|---|
