| Summary: | 博士 === 國立交通大學 === 應用化學系碩博士班 === 99 === In this thesis, the central idea is to develop materials for OLEDs, which will be utilized in the improvement of electrophosphorescence as well as electrofluorescence. The study is divided into two sub topics as following:
(1)Studies of host materials with bipolar characteristics
In part A, a solution-processable bipolar material tBu-OXDTFA comprising an electron-rich triphenylamine core and electron-deficient oxadiazole/fluorene peripheries was synthesized. This dendrimer-like molecule not only possesses a high triplet energy but also exhibits excellent film-forming properties upon solution processing. We achieved highly efficient blue and white electrophosphorescent OLEDs through solution processing. In the part B, we have prepared efficient red OLEDs incorporating POAPF as the host material doped with the osmium phosphor Os(fptz)2(PPh2Me)2. POAPF, which possesses bipolar functionalities, can facilitate both hole and electron injection from the charge transport layers to provide a balanced charge flux within the emission layer. In addition, we fabricated a POAPF-based white-light OLED - containing red- [doped with Os(fptz)2(PPh2Me)2] and blue-emitting [doped with FIrpic] layers - that also exhibited satisfactory efficiencies.
(2)Studies of multifunctional blue emitters containing triphenyl- phosphine oxide
First, we have synthesized a highly efficient blue-light emitter, POAn, which comprises electron-deficient triphenylphosphine oxide side groups appended to the 9- and 10-positions of a 2-tert-butylanthracene core. In addition to serving as an electron-transporting blue-light-emitting material, POAn also facilitates electron injection from the Al cathode to itself. Consequently, simple double-layer devices incorporating POAn as the emitting, electron-transporting, and -injecting material produce bright deep-blue lights. Furthermore, in part B, based on the advantage of triphenylphosphine oxide-based emitter, a novel bipolar blue emitter, TPAPOAn, bearing hole-transporting arylamine groups and electron-transporting triphenylphosphine oxide moieties was synthesized and incorporated into an efficient single-layer device, revealing very promising performances comparable to those of multi-layer blue-emitting devices.
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