Browsing by Author "Laskar, Inamur R."

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Highly efficient yellowish-white phosphorescent organic light-emitting devices
(2006-09-01)
Hsu, Shih-Feng
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Laskar, Inamur R.
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Chen, Teng-Ming
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Ma, Jie-Wei
;
Hwang, Shiao-Wen
We have developed highly efficient yellowish-white organic light-emitting devices (WOLEDs) with very broad emission based on a orange emitter, (2-2 '-(4-flurophenyl)benzothiozolato-N,C-2 ') platinum (acetylacetonate) [Pt(F-bt)acac]. A yellowish-white light device with one of the highest electroluminescent (EL) efficiencies of 19.68cd/A (10.94%) with Commission Internationale d'Eclairage (CIE) coordinates of (x,y) = (0.399,0.453) has been demonstrated.
Material Profiling for Photocrystallography: Relating Single-Crystal Photophysical and Structural Properties of Luminescent Bis-Cyclometalated Iridium-Based Complexes
(2013-05-01)
Cole, Jacqueline M.
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Bowes, Katharine F.
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Clark, Ian P.
;
Low, Kian Sing
;
Zeidler, Anita
The photophysical properties of seven luminescent iridium complexes are characterized in their single-crystal form, and the photoactivity is related to their molecular structures. Specifically, solid-state optical emission spectra and associated lifetimes are determined from single crystals of iridium complexes containing three bidentate ligands: two variously substituted 2-phenylbenzothiazoles and either a 2,4-pentadione (acetylacetone) or 2-pyridinecarboxylic (picolinic) acid. All complexes studied exhibit emissive behavior in the solid-state which originates from 3 pi-pi* and metal-to-ligand-charge-transfer (MLCT) electronic transitions; this is supported by density functional theory. Phosphorescence is observed in all cases with microsecond lifetimes, ranging from 0.30 to 2.4 mu s at 298 K and 1.4-4.0 mu s at 100 K. Structure-property relationships are established which are relevant to the potential solid-state application of this series of luminescent complexes as organic light emitting diodes (OLED) material components. In addition, these materials are assessed for their suitability to time-resolved pump-probe photocrystallography experiments, which will reveal their photoexcited state structure. Accordingly, the design process by which materials are selected and technical parameters are defined for a photocrystallography experiment is illustrated. This family of complexes presents a case study for this photocrystallography material profiling. Results show that the time-resolved photo excited state structure, featuring the MLCT transition is, in principle at least, viable for two of these complexes.
The synthesis new dendrimer and high quantum efficiency iridium complex properties of solution processable phosphorescent
(2006)
Hong, Hsiao-Wen
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Laskar, Inamur R.
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Chen, Teng-Ming
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應用化學系
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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%.
Three-wavelength white electrophosphorescence with two emissive materials
(2005)
Hsu, Shih-Feng
;
Laskar, Inamur R.
;
Chen, Teng-Ming
;
Hwang, Shiao-Wen
;
Chen, Chin H.
A New phosphorescent material based on Pt complex, Pt(btOMe)acac was synthesized and its specific EL emission spectrum from green to red combined with blue phosphorescent material. Firpic, can easily achieve high-efficiency three-wavelength white light with two emitters.