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Red Luminescence (red + luminescence)

Distribution by Scientific Domains
Polymers and Materials Science28%
Chemistry28%

Selected Abstracts

Luminescent Soft Material: Two New Europium-Based Ionic Liquids

HELVETICA CHIMICA ACTA, Issue 11 2009
Sifu Tang
Abstract Two new Eu-based ionic liquid systems, [C4mim][DTSA],:,[Eu(DTSA)3] and 2[C4mim] [DTSA],:,[Eu(DTSA)3] were synthesized at 120° under inert conditions from 1-butyl-1-methylimidazolium ditoluenesulfonylamide ([C4mim][DTSA]). The identity and purity of the synthesized compounds were confirmed by elemental analysis, IR, Raman, and 1H-NMR spectroscopy. As they solidify below 100° as glasses they qualify as ionic liquids. Fluorescence measurements show that the materials exhibit a strong red luminescence of high color purity. Therefore, they have the potential to be used for optical applications such as in emission displays. [source]

Preparation and Optical Property of Glass Ceramics Containing Ruby Crystals

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2010
Jumpei Ueda
We have developed the glass ceramics containing ruby crystals by heat treatment of a Cr3+ -doped SiO2,Al2O3,Y2O3 glass at 1550°C. The shape of precipitated crystals in the glass matrix was rod type whose average width and length were around 10 and 200 ,m, respectively. From an X-ray diffraction measurement and an electron probe X-ray microanalysis, it was confirmed that the rod crystals were ,-Al2O3. Intense emission bands of Cr3+ at 694 nm, called the R -lines, were observed in the glass ceramics heat treated above 1300°C. In addition, the intense red luminescence was observed only in the ,-Al2O3 rod crystals by a photoluminescence mapping image. [source]

Electron beam induced defects in Ge-implanted SiO2 layers

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2005
Roushdey Salh
Abstract Scanning electron microscopy (SEM) and cathodoluminescence (CL) have been used to investigate the irradiation-sensitive defect structure of pure and Ge+ -implanted amorphous silicon dioxide layers. CL emission spectra at specimen temperatures between liquid nitrogen (LNT) and room temperature (RT) are identified with particular defect centers including the nonbridging oxygen-hole center (NBOHC: ,Si,O,) associated with the red luminescence at 650 nm (1.9 eV), the self trapped exciton (STE) with the yellow-green luminescence at 580 nm (2.1 eV) and the Si related oxygen deficient center (SiODC) with the blue (460 nm; 2.7 eV) and ultraviolet UV band (295 nm; 4.2 eV). In Ge doped SiO2 an additional emission band is identified at (410 nm; 3.1 eV). This band corresponds to the Ge related oxygen deficient center (GeODC). The annealing process of Ge+ -implanted layer leads first to a strong increase of the violet luminescence due to formation of Ge dimers, trimers and higher aggregates, finally to destruction of the luminescence centers by further growing to Ge nanoclusters. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Detection of red luminescence with improved photocathodes

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2005
R. Downey
Abstract Measurement of luminescence from 700 to 1,000 nm has been improved both by retrofit designs on existing photomultiplier tubes and design of new cathode structures. Based on the S20 type multialkali photocathodes the enhanced systems offer improvements over conventional PM tubes from a factor of ,2 from 200 to 700 nm, increasing to ,25 times on progressing to longer wavelengths from 900 to beyond 1,100 nm. These gains offer major changes in sensitivity for detection of weak long wavelength emission bands, with improved signal to noise and reductions in problems of second order light. Indeed, previously ignored red emission bands may dominate the photon energy spectra in some cases. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Origin of red luminescence of sodium titanium phosphate crystals

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2005
R.S. Boyko
Abstract Sodium titanium orthophosphate NaTi2(PO4)3 crystals were synthesized and their luminescence properties were investigated. Luminescence spectra of this compound consist of two main bands in the green and red spectral regions. Maximum positions of the bands depend on temperature of the samples. At some conditions the red band reveals details of a fine spectra structure. Obtained results are discussed taking into account similarity of spectral properties of the investigated crystals with ones described recently for sodium aluminum diphosphate crystals doped with chromium ions. Conclusion is made that red emission band is corresponded to radiation transitions in the Ti3+ titanium ions. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

A novel calixarene-containing hyperbranched aliphatic polyester incorporated with pendant europium complexes

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 6 2009
Jichang Feng
Abstract A novel calixarene-containing hyperbranched aliphatic polyester incorporated with pendant europium complexes (H20-Cal-Eu) was synthesized and characterized by FTIR, UV, and element analysis. The polymer H20-Cal-Eu shows a glass-transition temperature (Tg) of 127°C, and a deposition temperature in the range of 280,600°C, as revealed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. The investigation on its photoluminescence (PL) properties revealed that the polymer emitted a remarkably strong red luminescence. Furthermore, its half spectral bandwidth of the polymer film is only about 10,nm as determined from luminescence spectra, suggesting that the light is nearly monochromatic. It is proposed that the hyperbranched polymer (HBP) containing rare earth element exhibits great potential as a red light emitting material. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Strength Enhancement of Nanostructured Organogels through Inclusion of Phthalocyanine-Containing Complementary Organogelator Structures and In Situ Cross-Linking by Click Chemistry

CHEMISTRY - A EUROPEAN JOURNAL, Issue 30 2008
David, Díaz Díaz Dr.
Abstract Stable photoactive organogels were successfully prepared by a two-step sequence involving: 1),formation of thermoreversible organogels by use of a combination of low-molecular-weight organogelators (LMOGs) and ZnII,phthalocyanine (ZnII,Pc) moieties containing complementary organogelator structures, and 2),strength enhancement of the gels by in situ cross-linking with the aid of CuI -catalysed azide,alkyne [3+2] cycloadditions (CuAACs). The optimum click reaction was carried out between a flexible C6 aliphatic diazide and a suitable dialkyne (molar ratio 1:1) added in a low proportion relative to the organogelator system [LMOG+ZnIIPc]. The dialkyne unit was incorporated into a molecule resembling the LMOGs structure in such a way that it could also participate in the self-assembly of [LMOG+ZnIIPc]. The significant compatibility of the multicomponent photoactive organogels towards this strengthening through CuAACs allowed their sol-to-gel transition temperatures (Tgel) to be enhanced by up to 15,°C. The Tgel values estimated by the "inverse flow method" were in good agreement with the values obtained by differential scanning calorimetry (DSC). Rheological measurements confirmed the viscoelastic, rigid, and brittle natures of all Pc-containing gels. Transmission and scanning electron microscopy (TEM, SEM) and atomic force microscopy (AFM) revealed the fibrilar nature of the gels and the morphological changes upon cross-linking by CuAAC. Emission of a red luminescence from the dry nanoscale fibrous structure,due to the self-assembly of the Pc-containing compounds in the organogel fibres,was directly observed by confocal laser scanning microscopy (CLSM). The optical properties were studied by UV/Vis and fluorescence spectroscopy. Fluorescence, Fourier-transform infrared (FTIR) and circular dichroism (CD) measurements were also carried out to complete the physicochemical characterization of selected gels. As a proof of concept, two different organogelators (cholesterol- and diamide-based LMOGs) were successfully used to validate the general strategy. [source]