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Color Coordinates (color + coordinate)
Selected AbstractsPhenylcarbazole-Based Phosphine Oxide Host Materials For High Efficiency In Deep Blue Phosphorescent Organic Light-Emitting DiodesADVANCED FUNCTIONAL MATERIALS, Issue 22 2009Soon Ok Jeon Abstract Highly efficient deep blue phosphorescent organic light-emitting diodes are developed using novel phenylcarbazole-based phosphine oxide host materials (PPO1 and PPO2). A deep blue phosphorescent dopant, tris((3,5-difluoro-4-cyanophenyl)pyridine) iridium, is doped into PPO1 and PPO2 at a doping concentration of 15% and a high quantum efficiency of 18.4% is obtained with color coordinates of (0.14, 0.15). [source] Highly Efficient Red Phosphorescent OLEDs based on Non-Conjugated Silicon-Cored Spirobifluorene Derivative Doped with Ir-ComplexesADVANCED FUNCTIONAL MATERIALS, Issue 3 2009Yi-Yeol Lyu Abstract A novel host material containing silicon-cored spirobifluorene derivative (SBP-TS-PSB), is designed, synthesized, and characterized for red phosphorescent organic light-emitting diodes (OLEDs). The SBP-TS-PSB has excellent thermal and morphological stabilities and exhibits high electroluminescence (EL) efficiency as a host for the red phosphorescent OLEDs. The electrophosphorescence properties of the devices using SBP-TS-PSB as the host and red phosphorescent iridium (III) complexes as the emitter are investigated and these devices exhibit higher EL performances compared with the reference devices with 4,4,- N,N,-dicarbazole-biphenyl (CBP) as a host material; for example, a (piq)2Ir(acac)-doped SBP-TS-PSB device shows maximum external quantum efficiency of ,ext,=,14.6%, power efficiency of 10.3 lm W,1 and Commission International de L'Eclairage color coordinates (0.68, 0.32) at J,=,1.5,mA cm,2, while the device with the CBP host shows maximum ,ext,=,12.1%. These high performances can be mainly explained by efficient triplet energy transfer from the host to the guests and improved charge balance attributable to the bipolar characteristics of the spirobifluorene group. [source] New Shade Guide for Evaluation of Tooth Whitening,Colorimetric StudyJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 5 2007RADE D. PARAVINA DDS ABSTRACT Statement of the Problem:, Available shade guides lack colorimetric uniformity, which compromises the validity of visual evaluation of tooth whitening efficacy. Purpose:, The objective of this study was to perform a colorimetric analysis of a new shade guide designed primarily for the visual evaluation of tooth whitening efficacy and to compare this shade guide with two commercial shade guides. Materials and Methods:, Color ranges and color distribution of three shade guides (prototype of the new Vita Bleachedguide 3D-Master [BG, Vita Zahnfabrik, Bad Säckingen, Germany], value scale of Vitapan Classical [VC, Vita], and color-ordered Trubyte Bioform porcelain shade guide [TB, Dentsply International, York, PA, USA]) were analyzed (N=3). A circular area (d=1.7 mm) on the middle of the labial surface of the tab, excluding the cervical portion, was measured with a spectroradiometer (D65, 2). Whiteness and yellowness indices were computed. Data were analyzed by analysis of variance and Fisher's PLSD test at a 0.05 level of significance. Results:, The range of color difference (,E*) from the lightest to the darkest tab was 33.8 (BG), 17.1 (VC), and 23.2 (TB). Mean values of ,E* among pairs of adjacent tabs were 3.0 (BG), 4.2 (VC), and 3.3 (TB). BG exhibited the highest R2 values between color coordinate pairs and between whiteness and yellowness indices with the respective color coordinates. Conclusions:, BG exhibited the widest color range and had the most consistent color distribution as compared with the two commercial products. Extension of the lightness range of BG toward higher L* values (bleach shades) was confirmed. CLINICAL SIGNIFICANCE A dental shade guide that is colorimetrically uniform might increase the reliability of visual comparisons of tooth whitening efficacy, whereas the inclusion of realistic bleaching shades in the shade guide will complement contemporary esthetic dentistry. (J Esthet Restor Dent 19:276,283, 2007) [source] Synthesis and electroluminescent properties of polyfluorene-based conjugated polymers containing bipolar groupsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 22 2009Sheng-Tung Huang Abstract A bipolar dibromo monomer, bis-(4-bromophenyl)[4-(3,5-diphenyl-1,2,4- triazole-4-yl)-phenyl]amine (9), containing electro-rich triphenylamine and electro-deficient 1,2,4-triazole moieties was newly synthesized and characterized. Two fluorescent fluorene-based conjugated copolymers (TPAF, TPABTF) were prepared via facile Suzuki coupling from the dibromo bipolar monomer, 4,7-dibromo-2,1,3-benzothiadiazole (BTDZ), and 9,9-dioctylfluorene. They were characterized by molecular weight determination, IR, NMR, DSC, TGA, solubility, absorption and photoluminescence spectra, and cyclic voltammetry. The polymers showed good solubility in common organic solvents such as dichloromethane, chloroform, tetrahydrofuran, and dichlorobenzene at room temperature. They had glass transition temperatures (Tg) higher than 135 °C and 5% degradation temperatures in nitrogen atmosphere were higher than 428 °C. Single layer polymer light-emitting diodes (PLED) of ITO/PEDOT:PSS/polymer/metal showed a blue emission at 444 nm and Commission Internationale de I'Eclairage (CIE) 1931 color coordinates of (0.16, 0.13) for TPAF. The device using TPABTF as emissive material showed electroluminescence at 542 nm with CIE1931 of (0.345, 0.625), low turn-on voltage of 5 V, a maximum electroluminance of 696 cd/m2, and a peak efficiency of 2.02 cd/A. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6231,6245, 2009 [source] Preparation and luminescent properties of Eu2+ -activated glass ceramic phosphor precipitated with ,-Ca2SiO4 and Ca3Si2O7PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2009Takayuki Nakanishi Abstract Eu2+: calcium silicate glass ceramics (GC) containing ,-Ca2SiO4 and Ca3Si2O7 crystal phosphors were fabricated by cerammization process from a GC that were prepared by a novel GC preparation; frozen sorbet method. The GC obtained (as-made GC) consisted of glass and spherical ,-Ca2SiO4 crystal phases with size of about 20,40 ,m. After post-ceramization, Ca3Si2O7 crystals were also precipitated. Judging from the cathodoluminescence (CL) mapping images, two emission bands peaked at 515 nm and 600 nm were observed from different parts in the GC. The observed photoluminescence (PL) have two broad emission bands at 515 nm from Eu2+: ,-Ca2SiO4 and at 600 nm from Eu2+:Ca3Si2O7. With increasing heat-treatment temperature, the color coordinates shifted from green range to center region, which corresponds to pure white in the CIE chromaticity diagram. Eu2+ doped calcium silicate GC containing ,-Ca2SiO4 and Ca3Si2O7 are suitable phosphor as the use of phosphor converting white light emitting diode (pc-wLED) with high color rendering. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Development and characterization of light-emitting diodes (LEDs) based on ruthenium complex single layer for transparent displaysPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2008G. Santos Abstract In this work, two ruthenium complexes, [Ru(bpy)3](PF6)2 and [Ru(ph2phen)3](PF6)2 in poly(methylmethacrylate) matrix were employed to build single-layer light-emitting electrochemical cells by spin coating on indium tin oxide substrate. In both cases the electroluminescence spectra exhibit a relatively broad band with maxima near to 625 nm and CIE (x, y) color coordinates of (0.64, 0.36), which are comparable with the photoluminescence data in the same medium. The best result was obtained with the [Ru(bpy)3](PF6)2 device where the optical output power approaches 10 µW at the band maximum with a wall-plug efficiency higher than 0.03%. The lowest driving voltage is about 4 V for an electrical current of 20 mA. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] White light generation through yellow nanophosphor and blue organic light-emitting diodePHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 4 2009Je Hong Park Abstract White light-emitting device (WLED) combining yellow-emitting nanophosphor and blue organic light-emitting diode (LED) was developed. WLED was fabricated by using a spin-coating method. Yellow-emitting nanophosphor was dispersed in the blue-emitting polymer solution for spin-coating. As a variation of mixture ratio of yellow-emitting nanophosphor and blue-emitting polymer in emitting layer, the emission spectra were studied. Our white organic light-emitting device with 30% phosphor mixture ratio and at the driving voltage of 17 V showed the color coordinates of x = 0.266 and y = 0.33. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Assessing the color of red wine like a taster's eyeCOLOR RESEARCH & APPLICATION, Issue 2 2009Begońa Hernández Abstract Color of 33 commercial red wines and five-color reference wines was measured in the same conditions in which visual color assessment is done by wine tasters. Measurements were performed in the two distinctive regions, center and rim, which are the regions assessed by wine tasters when the wine sampler is tilted. Commercial wines were classified into five color categories using the color specifications in their taste cards. The five color categories describe the spread of red hues found in red wines from the violet to brown nuances. The performance of CIELAB color coordinates in terms of their ability to reproduce the observed classification has been established using discriminant analysis. The CIELAB hue angle, hab, measured in the rim, where wine thickness is of the order of few millimeters, gives the best results classifying correctly 71.1% of the samples. Classification results are not significantly improved when additional color coordinates are considered. Moreover, ,E* color differences with color reference wines do not provide good classification results. The analysis of reference and commercial wines supports the fact that hue is the main factor in the classification done by wine tasters. This is reinforced by the linear correlation found between hab in the rim and the wine age (R2 = 0.795) in accordance with the fact that wines change their hues from violet to brown tints with ageing. © 2009 Wiley Periodicals, Inc. Col Res Appl, 34, 153,162, 2009 [source] | |||||||||||||