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CIE Coordinates (cie + coordinate)
Selected AbstractsStable, Glassy, and Versatile Binaphthalene Derivatives Capable of Efficient Hole Transport, Hosting, and Deep-Blue Light EmissionADVANCED FUNCTIONAL MATERIALS, Issue 15 2010Bin Wei Abstract Organic light-emitting diodes (OLEDs) have great potential applications in display and solid-state lighting. Stability, cost, and blue emission are key issues governing the future of OLEDs. The synthesis and photoelectronics of a series of three kinds of binaphthyl (BN) derivatives are reported. BN1,3 are "melting-point-less" and highly stable materials, forming very good, amorphous, glass-like films. They decompose at temperatures as high as 485,545,°C. At a constant current density of 25,mA,cm,2, an ITO/BN3/Al single-layer device has a much-longer lifetime (>80,h) than that of an ITO/NPB/Al single-layer device (8,h). Also, the lifetime of a multilayer device based on BN1 is longer than a similar device based on NPB. BNs are efficient and versatile OLED materials: they can be used as a hole-transport layer (HTL), a host, and a deep-blue-light-emitting material. This versatility may cut the cost of large-scale material manufacture. More importantly, the deep-blue electroluminescence (emission peak at 444 nm with CIE coordinates (0.16, 0.11), 3.23 cd A,1 at 0.21,mA cm,2, and 25200,cd,m,2 at 9,V) remains very stable at very high current densities up to 1000,mA,cm,2. [source] Molecular Engineering of Blue Fluorescent Molecules Based on Silicon End-Capped Diphenylaminofluorene Derivatives for Efficient Organic Light-Emitting MaterialsADVANCED FUNCTIONAL MATERIALS, Issue 8 2010Kum Hee Lee Abstract Blue fluorescent materials based on silicone end-capped 2-diphenylaminofluorene derivatives are synthesized and characterized. These materials are doped into a 2-methyl-9,10- di -[2-naphthyl]anthracene host as blue dopant materials in the emitting layer of organic light-emitting diode devices bearing a structure of ITO/DNTPD (60,nm)/NPB (30,nm)/emitting layer (30,nm)/Alq3 (20,nm)/LiF (1.0,nm)/Al (200,nm). All devices exhibit highly efficient blue electroluminescence with high external quantum efficiencies (3.47%,7.34% at 20,mA,cm,2). The best luminous efficiency of 11.2,cd,A,1 and highest quantum efficiency of 7.34% at 20,mA,cm,2 are obtained in a device with CIE coordinates (0.15, 0.25). A deep-blue OLED with CIE coordinates (0.15, 0.14) exhibits a luminous efficiency of 3.70,cd,A,1 and quantum efficiency of 3.47% at 20,mA,cm,2. [source] White Electroluminescence by Supramolecular Control of Energy Transfer in Blends of Organic-Soluble Encapsulated PolyfluorenesADVANCED FUNCTIONAL MATERIALS, Issue 2 2010Sergio Brovelli Abstract Here, it is demonstrated that energy transfer in a blend of semiconducting polymers can be strongly reduced by non-covalent encapsulation of one constituent, ensured by threading of the conjugated strands into functionalized cyclodextrins. Such macrocycles control the minimum intermolecular distance of chromophores with similar alignment, at the nanoscale, and therefore the relevant energy transfer rates, thus enabling fabrication of white-light-emitting diodes (CIE coordinates: x,=,0.282, y,=,0.336). In particular, white electroluminescence in a binary blend of a blue-emitting, organic-soluble rotaxane based on a polyfluorene derivative and the green-emitting poly(9,9-dioctylfluorene-alt-benzothiadiazole (F8BT) is achieved. Morphological and structural analyses by atomic force microscopy, fluorescence mapping, µ-Raman, and fluorescence lifetime microscopy are used to complement optical and electroluminescence characterization, and to enable a deeper insight into the properties of the novel blend. [source] Multifunctional Fluorene-Based Oligomers with Novel Spiro-Annulated Triarylamine: Efficient, Stable Deep-Blue Electroluminescence, Good Hole Injection, and Transporting Materials with Very High TgADVANCED FUNCTIONAL MATERIALS, Issue 24 2009Zuoquan Jiang Abstract A series of fluorene-based oligomers with novel spiro-annulated triarylamine structures, namely DFSTPA, TFSTPA, and TFSDTC, are synthesized by a Suzuki cross-coupling reaction. The spiro-configuration molecular structures lead to very high glass transition temperatures (197,253,°C) and weak intermolecular interactions, and consequently the structures retain good morphological stability and high fluorescence quantum efficiencies(0.69,0.98). This molecular design simultaneously solves the spectral stability problems and hole-injection and transport issues for fluorene-based blue-light-emitting materials. Simple double-layer electroluminescence (EL) devices with a configuration of ITO/TFSTPA (device A) or TFSDTC (device B)/ TPBI/LiF/Al, where TFSTPA and TFSDTC serve as hole-transporting blue-light-emitting materials, show a deep-blue emission with a peak around 432,nm, and CIE coordinates of (0.17, 0.12) for TFSTPA and (0.16, 0.07) for TFSDTC, respectively, which are very close to the National Television System Committee (NTSC) standard for blue (0.15, 0.07). The maximum current efficiency/external quantum efficiencies are 1.63,cd A,1/1.6% for device A and 1.91,cd A,1/2.7% for device B, respectively. In addition, a device with the structure ITO/DFSTPA/Alq3/LiF/Al, where DFSTPA acts as both the hole-injection and -transporting material, is shown to achieve a good performance, with a maximum luminance of 14,047,cd m,2, and a maximum current efficiency of 5.56,cd A,1. These values are significantly higher than those of devices based on commonly usedN,N,-di(1-naphthyl)- N,N,-diphenyl-[1,1,-biphenyl]-4,4,-diamine (NPB) as the hole-transporting layer (11,738,cd m,2 and 3.97,cd A,1) under identical device conditions. [source] Electroluminescence and Laser Emission of Soluble Pure Red Fluorescent Molecular Glasses Based on DithienylbenzothiadiazoleADVANCED FUNCTIONAL MATERIALS, Issue 18 2009Ju Huang Abstract Soluble molecular red emitters 1a/1b are synthesized by Stille coupling from 2-(3,5-di(1-naphthyl)phenyl)thiophene precursors. The compounds show emission maxima at ca. 610,nm in CH2Cl2 solution and 620,nm in solid films. Replacing the n -hexyl substituent by 4- sec -butoxyphenyl produces a marked increase of glass transition temperature (Tg) from 82,°C to 137,°C and increases the solubility in toluene and p -xylene, thus improving the film-forming properties. Cyclic voltammetry shows that the compounds can be reversibly oxidized and reduced around +1.10 and ,1.20,V, respectively. A two-layered electroluminescent device based on 1b produces a pure red light emission with CIE coordinates (0.646, 0.350) and a maximal luminous efficiency of 2.1,cd A,1. Furthermore, when used as a solution-processed red emitter in optically pumped laser devices, compound 1b successfully produces a lasing emission at ca. 650,nm. [source] Synthesis and Characterization of Red-Emitting Iridium(III) Complexes for Solution-Processable Phosphorescent Organic Light-Emitting DiodesADVANCED FUNCTIONAL MATERIALS, Issue 14 2009Seung-Joon Lee Abstract A new series of highly efficient red-emitting phosphorescent Ir(III) complexes, (Et-CVz-PhQ)2Ir(pic-N-O), (Et-CVz-PhQ)2Ir(pic), (Et-CVz-PhQ)2Ir(acac), (EO-CVz-PhQ)2Ir(pic-N-O), (EO-CVz-PhQ)2Ir(pic), and (EO-CVz-PhQ)2Ir(acac), based on carbazole (CVz)-phenylquinoline (PhQ) main ligands and picolinic acid N-oxide (pic-N-O), picolinic acid (pic), and acetylacetone (acac) ancillary ligands, are synthesized for phosphorescent organic light-emitting diodes (PhOLEDs), and their photophysical, electrochemical, and electroluminescent (EL) properties are investigated. All of the Ir(III) complexes have high thermal stability and emit an intense red light with an excellent color purity at CIE coordinates of (0.65,0.34). Remarkably, high-performance solution-processable PhOLEDs were fabricated using Ir(III) complexes with a pic-N-O ancillary ligand with a maximum external quantum efficiency (5.53%) and luminance efficiency (8.89,cd,A,1). The novel use of pic-N-O ancillary ligand in the synthesis of phosphorescent materials is reported. The performance of PhOLEDs using these Ir(III) complexes correlates well with the results of density functional theory calculations. [source] Solution-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] Solution-Processible Red Iridium Dendrimers based on Oligocarbazole Host Dendrons: Synthesis, Properties, and their Applications in Organic Light-Emitting Diodes,ADVANCED FUNCTIONAL MATERIALS, Issue 18 2008Junqiao Ding Abstract A series of novel red-emitting iridium dendrimers functionalized with oligocarbazole host dendrons up to the third generation (red-G3) have been synthesized by a convergent method, and their photophysical, electrochemical, and electroluminescent properties have been investigated. In addition to controlling the intermolecular interactions, oligocarbazole-based dendrons could also participate in the electrochemical and charge-transporting process. As a result, highly efficient electrophosphorescent devices can be fabricated by spin-coating from chlorobenzene solution in different device configurations. The maximum external quantum efficiency (EQE) based on the non-doped device configuration increases monotonically with increasing dendron generation. An EQE as high as 6.3% was obtained as for the third generation dendrimer red-G3, which is about 30 times higher than that of the prototype red-G0. Further optimization of the device configuration gave an EQE of 11.8% (13.0,cd A,1, 7.2,lm W,1) at 100,cd m,2 with CIE coordinates of (0.65, 0.35). The state-of-the-art performance indicated the potential of these oligocarbazole-based red iridium dendrimers as solution processible emissive materials for organic light-emitting diode applications. [source] Luminescence Properties of Aminobenzanthrones and Their Application as Host Emitters in Organic Light-Emitting Devices,ADVANCED FUNCTIONAL MATERIALS, Issue 3 2007M.-X. Yu Abstract A series of aminobenzanthrone derivatives, possessing a keto and an amino group on the aromatic ring, are synthesized and their photoluminescence (PL) and electroluminescence (EL) properties are studied in detail. These compounds emit strongly in solution and in the solid state, with the emission maxima in the range of 528,668,nm resulting from charge-transfer transitions from the amino group to the keto moiety. The emission wavelength depends greatly on the polarity of the solvent. A red shift of nearly 100,nm is observed from n -hexane to dichloromethane for each of these compounds. The PL quantum yields of these molecules also depend tremendously on the solvent. The values are between 88 and 70,% in n- hexane and decrease as the polarity of the solvent increases. The single-crystal X-ray diffraction data reveal that the aminobenzanthrone planes of these molecules stack in the crystals in an antiparallel head-to-tail fashion. This strong dipole,dipole interaction accounts for the observed red-shifted emissions of the aminobenzanthrone molecules in powders and in films relative to those in nonpolar solvents. Electroluminescent devices using aminobenzanthrone derivatives as the host emitters or dopants emit orange to red light in the range 590,645,nm. High brightness, current efficiency, and power efficiency are observed for some of these devices. For example, the device using N -(4- t -butylphenyl)- N -biphenyl-3-benzanthronylamine as the emitter gives saturated red light with a current efficiency of 1.82,cd,A,1, brightness of 11,253,cd,m,2, and Commission Internationale de l'Éclairage (CIE) coordinates of (0.64,0.36); the device using N -(2-naphthyl)- N -phenyl-3-benzanthronylamine as the emitter gives orange,red light with a current efficiency of 3.52,cd,A,1, brightness of 25,000,cd,m,2, and CIE coordinates of (0.61,0.38). [source] White Electroluminescence from a Phosphonate-Functionalized Single-Polymer System with Electron-Trapping EffectADVANCED MATERIALS, Issue 36 2009Xin Guo A novel strategy for obtaining white electroluminescence (EL) is based on the mechanism of electron trapping on host. Phosphonate-functionalized polyfluorene is chosen as host owing to its strong electron affinity. Electrons are confined mostly by host pendants in the EL process, which suppresses charge transfer from host to dopant. White EL with CIE coordinates of (0.34,0.35) is achieved. [source] Tunable Organophosphorus Dopants for Bright White Organic Light-Emitting Diodes with Simple StructuresADVANCED MATERIALS, Issue 12 2009Omrane Fadhel Efficient white-light-emitting LEDs have been constructed by varying the substitution pattern of phosphole derivatives and chemical modification of their P atoms, producing thermally stable derivatives that are used as suitable dopants in a blue-light-emitting host. The devices exhibit high brightness and, due to their simple structures, current-independent CIE coordinates. [source] High-Efficiency White-Light Emission from a Single Copolymer: Fluorescent Blue, Green, and Red Chromophores on a Conjugated Polymer Backbone,ADVANCED MATERIALS, Issue 8 2007J. Luo The synthesis and properties of a single copolymer incorporating well-separated blue, green, and red chromophores on a single conjugated polymer backbone are reported. This copolymer is shown to have CIE coordinates of (0.35,0.34) and a luminance efficiency of 6.2,cd,A,1. The color coordinates of the resulting white-light emission remained extremely stable over a wide range of driving voltages. [source] Cover Picture: Multilayer Polymer Light-Emitting Diodes: White-Light Emission with High Efficiency (Adv. Mater.ADVANCED MATERIALS, Issue 17 200517/2005) Abstract White-light-emitting polymer diodes can be fabricated by solution processing using a blend of luminescent semiconducting polymers and organometallic complexes as the emission layer, and water-soluble (or ethanol-soluble) polymers and/or small molecules as the hole-injection/transport layer (HIL/HTL) and the electron injection/transport layer (EIL/ETL), as reported on p.,2053 by Gong, Bazan, Heeger and co-workers. Illumination-quality light is obtained from these multilayer, high-performance devices, with stable CIE coordinates, color temperatures, and high color-rendering indices all close to those of "pure" white light. The cover illustration envisages the incorporation of the fabrication technique with low-cost manufacturing technology in order to produce large areas of high-quality white light. [source] PCPP derivatives containing carbazole pendant as hole transporting moiety for efficient blue electroluminescenceJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 5 2009Jinwoo Kim Abstract The syntheses and characterization of poly((2,6-(4,4-bis(4-((2-ethylhexyl)oxy)phenyl)-4H -cyclopenta[def]phenanthrene))- co -(2,6-(4,4-bis(4-(((9-carbazolyl)hexyl)oxy)phenyl))-4H- cyclopenta[def]phenanthrene)) (BCzPh-PCPPs) and poly((2,6-(4,4-bis(4-((2-ethylhexyl)oxy)phenyl)-4H -cyclopenta[def]phenanthrene))- co -(2,6-(4-(4-(((9-carbazolyl)hexyl)oxy)phenyl)-4-(4-((2-ethylhexyl)oxy)phenyl)-4H- cyclopenta[def]phenanthrene))) (CzPh-PCPPs), with carbazole unit as pendants, are presented. The carbazole moiety, which can improve the hole injection ability, was introduced as a pendant on the PCPP backbone. The devices of the polymers with the configurations of ITO/PEDOT:PSS/polymers/Ca/Al generate EL emission with maximum peaks at 400,450 nm, CIE coordinates of (x = 0.11,0.29, y = 0.11,0.33), low turn-on voltages of 4,6 V, maximum brightness of 60,810 cd/m2, and luminescence efficiencies of 0.04,0.22 cd/A. The PL spectra of CzPh-PCPPs films did not show any peak at around 550 nm, which corresponds to keto defect or aggregate/excimer formation, even after annealing for 30 h at 150 °C in air. Out of the series, CzPh-PCPP1 (PCPP derivative with 10% of carbazole moiety as pendant) shows blue emission with the maximum brightness of 810 cd/m2 at 9 V, and the highest luminescence efficiency of 0.22 cd/A at 395 mA/cm2. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1327,1342, 2009 [source] Synthesis and characterization of novel germanium-containing poly(p -phenylenevinylene) derivativesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 3 2008Hoon-Je Cho Abstract Novel blue-emitting germanium-containing poly(p -phenylenevinylene) (PPV) derivatives with well-defined conjugation lengths were synthesized via Wittig-condensation polymerizations. The polymers can be color-tuned by the introduction of various chromophores into the PPV-based polymer backbones. The photoluminescence (PL) spectra of the polymers, GePVK (containing carbazole moieties), GeMEH (containing dialkoxybenzene moieties), and GePTH (containing phenothiazine moieties), were found to exhibit blue, greenish blue, and green emissions, respectively. GePTH produces more red-shifted emission than GeMEH and GEPVK, resulting in green emission, and the solution and solid state PL spectra of GePVK consist of almost blue emission. The electroluminescence spectra of GeMEH and GePTH contain yellowy green and yellow colors, respectively. Interestingly, GePVK exhibits white emission with CIE coordinates of (0.33, 0.37) due to electroplex emission in the light-emitting diodes. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 979,988, 2008 [source] White-Light Emission from a Single Polymer with Singlet and Triplet Chromophores on the BackboneMACROMOLECULAR RAPID COMMUNICATIONS, Issue 24 2006Hongyu Zhen Abstract Summary: A strategy to generate an efficient white-light emission has been developed by mixing fluorescence and phosphorescence emission from a single polymer. Fluorene is used as the blue-emissive component, benzothiadiazole (BT) and the iridium complex [(btp)2Ir(tmd)] are incorporated into a polyfluorene backbone, respectively, as green- and red-emissive chromophores by Suzuki polycondensation. By changing the contents of BT and [(btp)2Ir(tmd)] in the polymer, the electroluminescence spectrum from a single polymer can be adjusted to achieve white-light emission. A white polymeric light-emitting diode (WPLED) with a structure of ITO/PEDOT:PSS/PVK/PFIrR1G03/CsF/Al shows a maximum external quantum efficiency of 3.7% and the maximum luminous efficiency of 3.9 cd,·,A,1 at the current density of 1.6 mA,·,cm,2 with the CIE coordinates of (0.33, 0.34). The maximum luminance of 4,180 cd,·,m,2 is achieved at the current density of 268 mA,·,cm,2 with the CIE coordinates of (0.31, 0.32). The white-light emissions from such polymers are stable in the white-light region at all applied voltages, and the electroluminescence efficiencies decline slightly with the increasing current density, thus indicating that the approach of incorporating singlet and triplet species into the polymer backbone is promising for WPLEDs. Structure of PFIrR1G04 and the EL spectra of its devices under various voltages. Device structure: ITO/PEDOT:PSS/PVK/polymer/CsF/Al. [source] | ||||||||||||||||||||||