Home About us Contact
|
Home About us Contact | ||
|
|
||
Photoluminescence Quantum Yield (photoluminescence + quantum_yield)
Selected AbstractsSolution-Processible Phosphorescent Blue Dendrimers Based on Biphenyl-Dendrons and Fac -tris(phenyltriazolyl)iridium(III) Cores,ADVANCED FUNCTIONAL MATERIALS, Issue 19 2008Shih-Chun Lo Abstract Solution-processible saturated blue phosphorescence is an important goal for organic light-emitting diodes (OLEDs). Fac -tris(5-aryltriazolyl)iridium(III) complexes can emit blue phosphorescence at room temperature. Mono- and doubly dendronized fac -tris(1-methyl-5-phenyl-3- n -propyl-1H -[1,2,4]triazolyl)iridium(III) 1 and fac -tris{1-methyl-5-(4-fluorophenyl)-3- n -propyl-1H -[1,2,4]triazolyl}iridium(III) 4 with first generation biphenyl-based dendrons were prepared. The dendrimers emitted blue light at room temperature and could be solution processed to form thin films. The doubly dendronized 3 had a film photoluminescence quantum yield of 67% and Commission Internationale de l'Eclairage (CIE) coordinates of (0.17, 0.33). OLEDs comprised of a neat film of dendrimer 3 and an electron transport layer achieved a brightness of 142,cd m,2 at 3.8,V with an external quantum efficiency of 7.9%, and CIE coordinates of (0.18, 0.35). Attachment of the fluorine atom to the emissive core had the effect of moving the luminescence to shorter wavelengths but also quenched the luminescence of the mono- and doubly dendronized dendrimers. [source] Novel Heteroleptic CuI Complexes with Tunable Emission Color for Efficient Phosphorescent Light-Emitting Diodes,ADVANCED FUNCTIONAL MATERIALS, Issue 15 2007Q. Zhang Abstract A series of orange-red to red phosphorescent heteroleptic CuI complexes (the first ligand: 2,2,-biquinoline (bq), 4,4,-diphenyl-2,2,-biquinoline (dpbq) or 3,3,-methylen-4,4,-diphenyl-2,2,-biquinoline (mdpbq); the second ligand: triphenylphosphine or bis[2-(diphenylphosphino)phenyl]ether (DPEphos)) have been synthesized and fully characterized. With highly rigid bulky biquinoline-type ligands, complexes [Cu(mdpbq)(PPh3)2](BF4) and [Cu(mdpbq)(DPEphos)](BF4) emit efficiently in 20,wt,% PMMA films with photoluminescence quantum yield of 0.56 and 0.43 and emission maximum of 606,nm and 617,nm, respectively. By doping these complexes in poly(vinyl carbazole) (PVK) or N -(4-(carbazol-9-yl)phenyl)-3,6-bis(carbazol-9-yl) carbazole (TCCz), phosphorescent organic light-emitting diodes (OLEDs) were fabricated with various device structures. The complex [Cu(mdpbq)(DPEphos)](BF4) exhibits the best device performance. With the device structure of ITO/PEDOT/TCCz:[Cu(mdpbq)(DPEphos)](BF4) (15,wt,%)/TPBI/LiF/Al (III), a current efficiency up to 6.4,cd,A,1 with the Commission Internationale de L'Eclairage (CIE) coordinates of (0.61, 0.39) has been realized. To our best knowledge, this is the first report of efficient mononuclear CuI complexes with red emission. [source] Facile Synthesis of Fe2O3 Nanocrystals without Fe(CO)5 Precursor and One-Pot Synthesis of Highly Fluorescent Fe2O3,CdSe NanocompositesADVANCED MATERIALS, Issue 8 2009Chung Yen Ang ,-Fe2O3 nanocrystals are synthesized in high yield (2,g) without a hazardous precursor and with a less-expensive oxidant in a one-pot synthesis (see figure). Bifunctional magnetic quantum-dot (, -Fe2O3,CdSe) nanocomposites are also synthesized in high yield, with a photoluminescence quantum yield of up to 42%. [source] Synthesis and Characterization of New Types of Perylene Bisimide-Containing Conjugated Copolymers,MACROMOLECULAR RAPID COMMUNICATIONS, Issue 9 2005Xiaorong He Abstract Summary: Two new poly(perylene bisimide) polymers that contain biphenyl (PPery) and anthracene (PPeAn) groups at the bay position of perylene bisimide are designed and synthesized. The images of scanning and transmission electron microscopies for PPery and PPeAn show that both polymers form uniform nanoparticles. These copolymers emit red photoluminescence at around 640 nm with a relatively high photoluminescence quantum yield, 48% (in solution) for PPery and 68% (in solution) for PPeAn. Structures of the new copolymers synthesized here: PPery and PPeAn. [source] Liquid-crystalline and light-emitting polyacetylenesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 17 2003Jacky W. Y. Lam Abstract Rigid polymer backbones have often been considered to be detrimental to the packing of mesogenic pendants, and polyacetylenes have generally been regarded as unpromising materials for light-emitting applications. Our group, however, has succeeded in creating a series of liquid-crystalline polyacetylenes with rigid backbones and a variety of light-emitting polyacetylenes with luminescent chromophores. Here we demonstrate that the rigid polyacetylene skeleton can play a constructive role in guiding the alignments of mesogenic pendants and prove that polyacetylenes can be highly emissive with photoluminescence quantum yields of up to 98% and electroluminescence performances comparable or superior to those of the best blue-light-emitting polymers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2607,2629, 2003 [source] Preparation of Highly Luminescent CdTe/CdS Core/Shell Quantum DotsCHEMPHYSCHEM, Issue 4 2009Jian Wang Abstract A good balance: Oil-soluble CdTe/CdS core/shell quantum dots (QDs) that emit in the visible and near-infrared spectral regions with quantum yields up to 92,% (see figure) are prepared by balancing the coordinating capacity and the activation effect of selected surfactants. An effective shell-coating route is developed for covering oil-soluble CdTe quantum dots (QDs), which usually tend to aggregate during the heating-up process involved in shell formation. The new route is based on balancing the coordinating capacity and the activation effect of selected surfactants. The thus obtained highly luminescent CdTe/CdS core/shell QDs exhibit photoluminescence quantum yields as high as 92,%,among the best results obtained so far for luminescent semiconductor nanocrystals. By changing the size of the CdTe core, or the thickness of the CdS shell, the emission colors of the obtained core/shell nanocrystals can be tuned between the visible and near-infrared regions of the spectrum following an identical procedure. [source] | ||||||||||||||||||||||