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White Light Emission (white + light_emission)
Selected AbstractsSimple and Efficient Generation of White Light Emission From Organophosphorus Building BlocksADVANCED FUNCTIONAL MATERIALS, Issue 22 2009Carlos Romero-Nieto Abstract This paper describes a structure,property study using two dithieno[3,2- b;2,,3,- d]phosphole building blocks for the generation of white light emission and the incorporation of these units in a single polystyrene material. The emission of one of the light-emitting organophosphorus building blocks can efficiently be switched from orange to green by simple protonation of the amino functional groups that are part of the , -conjugated scaffold. The resulting three components (blue, green, and orange) exhibit photophysical properties that allow for an efficient fluorescence resonance energy transfer (FRET) in the mixture/polymer and provide intense white fluorescence upon excitation of the blue component; the fluorescence is close to pure white in solution and similar to the emission of an incandescent light bulb in the thin film. The results nicely illustrate the intriguing features that can be obtained by exclusively using organophosphorus-based organic electronic materials. [source] White electroluminescence from a single polyfluorene containing bis-DCM unitsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2007Sang Kyu Lee Abstract A series of fluorene-based copolymers composed of blue- and orange-light-emitting comonomers were synthesized through palladium-catalyzed Suzuki coupling reactions. 9,9-Dihexylfluorene and 2-(2,6-bis-{2-[1-(9,9-dihexyl-9H -fluoren-2-yl)-1,2,3,4-tetrahydroquinolin-6-yl]-vinyl}-pyran-4-ylidene)-malononitrile (DCMF) were used as the blue- and orange-light-emitting chromophores, respectively. The resulting single polymers exhibited simultaneous blue (423/450 nm) and orange (580,600 nm) emissions from these two chromophores. By adjusting the fluorene and DCMF contents, white light emission could be obtained from a single polymer; a device with an ITO/PEDOT:PSS/polymer/Ca/Al configuration was found to exhibit pure white electroluminescence with Commission Internationale de L'Eclairage (CIE) coordinates of (0.33, 0.31), a maximum brightness of 1180 cd/m2, and a current efficiency of 0.60 cd/A. Furthermore, the white light emission of this device was found to be very stable with respect to variation of the driving voltage. The CIE coordinates of the device were (0.32, 0.29), (0.32, 0.29), and (0.33, 0.31) for driving voltages of 7, 8, and 10 V, respectively. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3380,3390, 2007 [source] GaN nanorods and LED structures grown on patterned Si and AlN/Si substrates by selective area growthPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7-8 2010Shunfeng Li Abstract GaN nanorods (NRs) show promising applications in high-efficiency light emitting diodes, monolithic white light emission and optical interconnection due to their superior properties. In this work, we performed GaN nanostructures growth by pre-patterning the Si and AlN/Si substrates. The pattern was transferred to Si and AlN/Si substrates by photolithography and inductively-coupled plasma etching. GaN NRs were grown on these templates by metal-organic vapour phase epitaxy (MOVPE). GaN grown on Si pillar templates show a truncated pyramidal structure. Transmission electron microscopy measurements demonstrated clearly that the threading dislocations bend to the side facets of the GaN nanostructures and terminate. GaN growth can also be observed on the sidewalls and bottom surface between the Si pillars. A simple phenomenological model is proposed to explain the GaN nanostructure growth on Si pillar templates. Based on this model, we developed another growth method, by which we grow GaN rod structures on pre-patterned AlN/Si templates. By in-situ nitridation and decreasing of the V/III ratio, we found that GaN rods only grew on the patterned AlN/Si dots with an aspect ratio of about 1.5 - 2. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||