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Solid-state Lighting (solid-state + lighting)
Selected AbstractsEfficient Polymer White-Light-Emitting Devices for Solid-State LightingADVANCED MATERIALS, Issue 41 2009Hongbin Wu Highly efficient polymer white-light-emitting devices with a single emission layer containing a sky,blue triplet emitter and some home-made yellow phosphorescent iridium complexes doped into a polymer host are fabricated. The optimized devices present CIE coordinates of (0.395,0.452) at a current density of 12,mA,cm,2. [source] Stable, 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] Recent Advances in White Organic Light-Emitting Materials and Devices (WOLEDs)ADVANCED MATERIALS, Issue 5 2010Kiran T. Kamtekar Abstract WOLEDs offer new design opportunities in practical solid-state lighting and could play a significant role in reducing global energy consumption. Obtaining white light from organic LEDs is a considerable challenge. Alongside the development of new materials with improved color stability and balanced charge transport properties, major issues involve the fabrication of large-area devices and the development of low-cost manufacturing technology. This Review will describe the types of materials (small molecules and polymers) that have been used to fabricate WOLEDs. A range of device architectures are presented and appraised. [source] Log-Pile TiO2 Photonic Crystal for Light Control at Near-UV and Visible WavelengthsADVANCED MATERIALS, Issue 4 2010Ganapathi Subramania Three-dimensional photonic crystals with an omnidirectional bandgap at visible frequencies can have significant impact on solid-state lighting and solar-energy conversion. Using a procedure based on multistep electron-beam lithographic processing, a 9-layer log-pile photonic crystal is fabricated composed of 70-nm-wide titanium dioxide rods with 250-nm lattice spacing that exhibit a stacking direction bandgap between 400,nm and 500,nm (see image). [source] A Novel Narrow Band Red-Emitting Phosphor for White Light Emitting DiodesINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 4 2009Sivakumar Vaidyanathan Research on down conversion phosphor materials is the key for the development of solid-state lighting (SSL). Especially finding alternative red phosphor for white light emitting diodes (LEDs) based on blue or near ultraviolet (NUV) LEDs is important research task. In this view, we have synthesized a series of Eu3+ -substituted La2W2,xMoxO9 (x=0,2, in step of 0.3) red phosphor and characterized by X-ray diffraction (XRD) and photoluminescence. XRD results reveal a phase transition from triclinic to cubic structure for x>0.2. All the compositions show broad charge transfer (CT) band due to CT from oxygen to tungsten/molybdenum and red emission due to Eu3+ ions. Select compositions show high red emission intensity compared with the commercial red phosphor under NUV/blue ray excitation. Hence, this candidate can be a possible red phosphor for white LEDs. [source] Preparation and Photoluminescence Properties of Novel Color-Tunable MgY4Si3O13:Ce3+, Tb3+ Phosphors for Ultraviolet Light-Emitting DiodesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2010Hau-Yun Chung Oxide-based phosphors MgY4Si3O13 codoped with Ce3+ and Tb3+ were prepared in this study. Broad Ce3+ excitation spectra with the highest intensity at 330 nm were found for MgY4Si3O13:Ce3+, Tb3+ phosphors. Emission lines ranging from 450 to 650 nm originated from the 5D4,7FJ (J=6, 5, 4, 3) transitions of Tb3+ ions. The energy transfer from Ce3+ to Tb3+ occurred effectively in MgY4Si3O13:Ce3+, Tb3+ with a dipole,quadrupole interaction. Codoping Ce3+ with Tb3+ significantly increased the emission intensity of the prepared phosphors. Increasing the Tb3+ concentration led to the chromaticity coordinates of the prepared samples greatly shifting from the blue to the green region, extending the applicability of MgY4Si3O13:Ce3+, Tb3+ phosphors in solid-state lighting. 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