Browsing by Author "Hong, Hsiao-Wen"

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Effect of substituents on the photoluminescent and electroluminescent properties of substituted cyclometalated iridium(III) complexes
(2007-01-15)
Hong, Hsiao-Wen
;
Chen, Teng-Ming
;
應用化學系
;
Department of Applied Chemistry
The photophysics of octahedral 4d(6) and 5d(6) Complexes has been studied extensively. The d(6) iridium(III) complexes show intense phosphorescence at room temperature. Our goal of this research is to study the synthesis, characterization and applications of the light emitting dopants based on iridium(III) complexes. We have prepared and characterized a series of substituted (4-CF3, 4-Me, 4-OMe, 4-F, 3-F) 2-phenylbenzoxazole ligand. The intermediate di-irrido and the six-coordinated mononuclear iridium(III) dopants of the above ligands have been synthesized and characterized. These complexes are thermally stable between 280-320 degrees C depending upon the substituents and sublimable. They emit bright yellow to green light. The peak emission wavelengths of the dopants can be finely tuned depending upon the electronic properties of the substituents as well as their positions in the ring. The emission spectral diagrams show that the emissive states of the complexes have major contribution of MLCT state. In the absorption spectra, the (MLCT)-M-1 and (MLCT)-M-3 transitions have been resolved in the range, 385-500 nm. The physical parameters of the electroluminescent devices for the substituted and the unsubstituted complexes has been compared and discussed. (c) 2006 Elsevier B.V. All rights reserved.
Syntheses, photoluminescence and electroluminescence of some new phosphorescent iridium(III)-based materials
(2005)
Hong, Hsiao-Wen
;
Chen, Teng-Ming
;
應用化學系
;
Department of Applied Chemistry
The research activities inspired us to initiate a systematic study to observe the color tuning of the iridium(III) complexes by choosing a particular cyclometalated ligand with substituents exhibiting different electronic properties. Tuning of maximum emission wavelengths depending upon the extent of conjugation and/or ring size and the effect of hetero atom will also be discussed.
Synthesis and electroluminescence studies of the, new iridium(III) complexes with 2-phenyl-1-pyrroline ligands
(2006-09-01)
Hong, Hsiao-Wen
;
Chen, Teng-Ming
;
應用化學系
;
Department of Applied Chemistry
Organic triplet-state light-emitting materials (organic phosphorescent dopants) have been one of the most important recent developments in the field of organic light-emitting diodes (OLEDs). Cyclopentane-containing cyclometalated iridium(III) complexes are rarely found in the literature. This inspired us to investigate the electroluminescence (EL) of these complexes. This work involves a systematic study for observing the color tuning of the iridium(III) complexes by choosing a predesigned cyclometalated ligand with substituents exhibiting different electronic properties. The tuning of maximum emission wavelengths depending on the extent of conjugation and/or ring size and also the effect of a hetero atom are discussed.
The synthesis new dendrimer and high quantum efficiency iridium complex properties of solution processable phosphorescent
(2006)
Hong, Hsiao-Wen
;
Laskar, Inamur R.
;
Chen, Teng-Ming
;
應用化學系
;
Department of Applied Chemistry
We demonstrate that the Ir complexes used as dopants in organic electrophosphorescent diodes exhibit high PL quantum efficiency (eta(PL)) in the solid-state. We have pursued the development of highly luminescent solution-processible electrophosphorescent dendrimers. We observed that the PLQY of the (GI-bt(3)Ir) compound dendrimer was approximately 1.5 times higher than the pristine complex Ir(bt)(3) in solution. The external quantum efficiency of OLEDs using the film containing a mixture of the first-generation dendrimer and an electron-transporting material was as high as 4.14%.