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Strong Photoluminescence (strong + photoluminescence)

Distribution by Scientific Domains

Polymers and Materials Science	57%
Chemistry	28%

Distribution within Polymers and Materials Science

General & Introductory Materials Science	49%

Selected Abstracts

ZnO:Eu Thin-Films: Sol,Gel Derivation and Strong Photoluminescence from 5D0 , 7F0 Transition of Eu3+ Ions.

CHEMINFORM, Issue 24 2007
Peiliang Chen
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Rational Color Tuning and Luminescent Properties of Functionalized Boron-Containing 2-Pyridyl Pyrrolide Complexes,

ADVANCED FUNCTIONAL MATERIALS, Issue 4 2005
H.-Y. Chen
Abstract Three systematically functionalized pyrrolide ligands were prepared via the coupling of methyl vinyl ketone and the respective carbaldehyde reagents, followed by treatment of the pre-formed dicarbonyl compounds with (NH4)2CO3 in order to generate the required pyrrole fragment. These ligands readily reacted with the boron reagent BPh3 to afford the complexes [(pyro)BPh2] (2a), [(noro)BPh2] (2b), and [(xaro)BPh2] (2c), where (pyro)H, (noro)H, and (xaro)H represents the 2-pyridyl, 2-quinolinyl, and 2-quinoxalinyl pyrrole groups, respectively. Complexes 2a,2c give stable solutions in air, and show strong photoluminescence with emission peak maxima located at 490,nm, 510,nm, and 575,nm, respectively. Calculations based upon time-dependent density function theory (TDDFT) show that the S1 state in these complexes is attributed to an allowed (,-symmetry),,,,* (,-symmetry) transition located at the chelating pyrrolide moieties. Electroluminescence (EL) devices based on 2c were fabricated. The EL emission from 2c as the host-emitter, with the emission peak maximum shifted to 580,nm, was observed when BCP was used as the hole blocking material. This device produces saturated red-orange light-emission at an onset voltage of 8,V and a maximum brightness of 5000,cd,m,2 at a driving voltage of 15,V; the external quantum yield is estimated to be 0.5,%. [source]

Simple and Efficient Near-Infrared Organic Chromophores for Light-Emitting Diodes with Single Electroluminescent Emission above 1000,nm,

ADVANCED MATERIALS, Issue 1 2009
Gang Qian
A series of NIR organic chromophores with donor,,,acceptor,,,donor structure are synthesized. Good thermal stability and strong photoluminescence in solid state render them suitable for application in light-emitting diodes. Exclusive near-infrared emission at 1080,nm with external quantum efficiency of 0.28% is obtained from the nondoped OLEDs. The longest electroluminescence wavelength is 1220,nm. [source]

Red Emitting Diphenylpyrrolopyrrole (DPP)-Based Polymers Prepared by Stille and Heck Coupling

MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 23 2006
Yu Zhu
Abstract Summary: Six new soluble conjugated polymers are described, which were prepared by Stille and Heck polycondensation reactions. They alternately consist of dialkylated 1,4-diketo-3,6-diphenyl-pyrrolo[3,4-c]pyrrole (DPP) units and divinylbenzene or thiophene-based units. The polymers were prepared from 1,4-diketo-2,5-dialkyl-3,6-di(4-bromophenyl)-pyrrolo[3,4-c]pyrrole with alkyl being hexyl (1a), methyl (1b), and 2-ethylhexyl (1c) and 2,5-bis(tributylstannyl)thiophene (2), 5,5,-bis(tributylstannyl)bithiophene (3), 3,4-ethylenedioxythiophene (4) and divinylbenzene (5). The new polymers exhibit brilliant red purple color and strong photoluminescence in common organic solvents. The DPP-phenylenevinylene copolymers exhibit molecular weights up to 41,000 Da, and the poly(DPP-thienylene)s up to 12,200 Da. In chloroform, the poly(DPP-thienylene)s exhibit absorption and photoluminescence maxima up to 560 and 624 nm, respectively, the corresponding maxima of the poly(DPP-phenylenevinylene)s are at 529 and 640 nm, respectively. Quantum yields of fluorescence up to 36% were determined. Cyclic voltammetric studies indicate quasi-reversible oxidation (p -doping) of the poly(DPP-thienylene)s and irreversible reduction (n -doping) of all polymers. Molecular structure of polymers. [source]

High quality InAs quantum dots covered by InGaAs/GaAs hetero-capping layer

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3 2003
R. Ohtsubo
Abstract Self-assembled InAs quantum dots with high performance were fabricated by molecular beam epitaxy via Stranski,Krastanov growth mode and InGaAs/GaAs hetero-capping growth. The size and shape of the dots were modified during the first GaAs capping layer, which plays an important role of a reduction in the inhomogeneous broadening. In particular, when the substrate temperature of the GaAs capping layer was 450,°C, the PL linewidth decreased to less than 20,meV. In order to reduce the residual strain in the InAs QDs and the capping layer, the InGaAs capping layer was additionally grown on the InAs dots covered by the first GaAs capping layer. As a result, the presented InGaAs/GaAs hetero-capping layer induced strong photoluminescence (PL) intensity, narrow PL linewidth and 1.3,,m light emission at room temperature. [source]

Heterocyclic polyimides containing siloxane groups in the main chain

POLYMER INTERNATIONAL, Issue 9 2009
Mariana-Dana Damaceanu
Abstract BACKGROUND: Among the polymers widely studied for applications in advanced techniques, aromatic polyimides have received considerable attention due to their outstanding thermal stability associated with good electrical and mechanical properties. However, these polymers are usually difficult to process, being insoluble and without a glass transition. To improve the processing characteristics of polyimides, modification of their structure is often achieved by the introduction of flexible linkages in the macromolecular chain or various substituents on the aromatic rings. RESULTS: A series of polyimides and intermediate polyamidic acids were synthesized from aromatic oxadiazole-diamines and a dianhydride containing a siloxane bridge (R2SiOSiR2). These polymers exhibit good solubility in certain organic solvents and can be cast into thin and very thin films from their solutions. They exhibit high thermal stability with decomposition being above 440 °C and relatively low glass transition temperatures in the range 160,190 °C. These polymers show strong photoluminescence in the blue spectral region. CONCLUSION: The introduction of oxadiazole rings together with siloxane groups into the chains of aromatic polyimides gives highly thermostable polymers with remarkable solubility and film-forming ability and that emit blue light, being attractive for applications in micro- and nanoelectronics and other related advanced fields. Copyright © 2009 Society of Chemical Industry [source]

Experimental and Theoretical Investigation of the Room-Temperature Photoluminescence of Amorphized Pb(Zr,Ti)O3

CHEMPHYSCHEM, Issue 8 2005
Emmanuelle Orhan Dr.
Abstract Ultrafine PbZr0.20Ti0.80O3 was amorphized through high-energy mechanical milling. The structural evolution through the amorphization process was accompanied by various characterization techniques, such as X-ray diffraction, Fourier-transformed IR spectroscopy (FTIR), high-resolution transmission electron microscopy (HR-TEM), and Raman spectroscopy. A strong photoluminescence was measured at room temperature for amorphized PbZr0.20Ti0.80O3, and interpreted by means of high-level quantum mechanical calculations in the density functional theory framework. Three periodic models were used to represent the crystalline and amorphized PbZr0.20Ti0.80O3, and they allowed the calculation of electronic properties that are consistent with the experimental data and that explain the appearance of photoluminescence. [source]