Browsing by Keywords "Light emitting diodes"
Now showing items 1-20 of 70
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Accuracy limits of distance estimation in visible light systems with RGB LEDs
(IEEE, 2019-09)The distance estimation problem is investigated for visible light positioning (VLP) systems with red-green-blue (RGB) light emitting diodes (LEDs). The accuracy limits on distance estimation are calculated in terms of the ... -
A bright cadmium-free, hybrid organic/quantum dot white light-emitting diode
(American Institute of Physics, 2012-12-06)We report a bright cadmium-free, InP-based quantum dot light-emitting diode (QD-LED) with efficient green emission. A maximum brightness close to 700 cd/m2 together with a relatively low turn-on voltage of 4.5 V has been ... -
A charge inverter for III-nitride light-emitting diodes
(American Institute of Physics Inc., 2016)In this work, we propose a charge inverter that substantially increases the hole injection efficiency for InGaN/GaN light-emitting diodes (LEDs). The charge inverter consists of a metal/electrode, an insulator, and a ... -
Circularly configured multi-SLM holographic display system
(IEEE, 2011)The designed circular holographic display system produces ghost-like 3D optical reconstructions of a computer generated 3D model. System uses six phase-only reflective-type spatial light modulators (SLMs) that are configured ... -
Colloidal nanocrystals embedded in macrocrystals: methods and applications
(American Chemical Society, 2016)Colloidal semiconductor nanocrystals have gained substantial interest as spectrally tunable and bright fluorophores for color conversion and enrichment solids. However, they suffer from limitations in processing their ... -
Colloidal quantum dot light-emitting diodes employing phosphorescent small organic molecules as efficient exciton harvesters
(American Chemical Society, 2014)Nonradiative energy transfer (NRET) is an alternative excitation mechanism in colloidal quantum dot (QD) based electroluminescent devices (QLEDs). Here, we develop hybrid highly spectrally pure QLEDs that facilitate energy ... -
Construction of multi-layered white emitting organic nanoparticles by clicking polymers
(Royal Society of Chemistry, 2015)A series of blue, green and red emitting polymers that are appropriately functionalized with alkyne and azide functional groups have been prepared and clicked together to construct bi-layered and tri-layered white emitting ... -
Controlled growth and characterization of epitaxially-laterally-overgrown InGaN/GaN quantum heterostructures
(IEEE, 2010)Crystal material quality is fundamentally important for optoelectronic devices including laser diodes and light emitting diodes. To this end epitaxial lateral overgrowth (ELO) has proven to be a powerful technique for ... -
Cooperative localization in hybrid infrared/visible light networks: Theoretical limits and distributed algorithms
(Institute of Electrical and Electronics Engineers, 2019)Light emitting diode (LED) based visible light positioning (VLP) networks can provide accurate location information in environments where the global positioning system (GPS) suffers from severe signal degradation and/or ... -
Critical role of CdSe nanoplatelets in color-converting CdSe/ZnS nanocrystals for InGaN/GaN light-emitting diodes
(OSA - The Optical Society, 2016)Here we report CdSe nanoplatelets that are incorporated into color-converting CdSe/ZnS nanocrystals for InGaN/GaN light-emitting diodes. The critical role of CdSe nanoplatelets as an exciton donor for the color conversion ... -
Cucurbit [7] uril-threaded fluorene-thiophene-based conjugated polyrotaxanes
(Royal Society of Chemistry, 2016)Here we investigate the effect of cucurbit[7]uril (CB7) on the thermal and optical properties of fluorene-thiophene based conjugated polyelectrolytes. For this purpose, poly(9,9′-bis(6′′-(N,N,N-trimethylammonium)hexyl)fl ... -
Distributed contact flip chip InGaN/GaN blue LED; comparison with conventional LEDs
(Elsevier, 2019)This paper presents high performance, GaN/InGaN-based light emitting diodes (LEDs) in three different device configurations, namely Top Emitting (TE) LED, conventional Flip Chip (FC) and Distributed Contact (DC) FC. Series ... -
The effect of growth conditions on the optical and structural properties of InGaN/GaN MQW LED structures grown by MOCVD
(Gazi University Eti Mahallesi, 2014)Five period InGaN/GaN MQW LED wafers were grown by low pressure MOCVD on an AlN buffer layer, which was deposited on a c-plane (0001)-faced sapphire substrate. The effect of growth conditions, such as the well growth time, ... -
Electroluminescence efficiency enhancement in quantum dot light-emitting diodes by embedding a silver nanoisland layer
(Wiley-VCH Verlag, 2015)A colloidal quantum dot light-emitting diode (QLED) is reported with substantially enhanced electroluminescence by embedding a thin layer of Ag nanoislands into hole transport layer. The maximum external quantum efficiency ... -
Energy-saving quality road lighting with colloidal quantum dot nanophosphors
(Walter de Gruyter GmbH, 2014)Here the first photometric study of road-lighting white light-emitting diodes (WLEDs) integrated with semiconductor colloidal quantum dots (QDs) is reported enabling higher luminance than conventional light sources, ... -
Enhanced hole transport in InGaN/GaN multiple quantum well light-emitting diodes with a p-type doped quantum barrier
(Optical Society of America, 2013)We study hole transport behavior of InGaN/GaN light-emitting diodes with the dual wavelength emission method. It is found that at low injection levels, light emission is mainly from quantum wells near p-GaN, indicating ... -
Enhanced optical characteristics of light emitting diodes by surface plasmon of Ag nanostructures
(SPIE, 2011)We investigated the surface plasmon coupling behavior in InGaN/GaN multiple quantum wells at 460 nm by employing Ag nanostructures on the top of a roughened p-type GaN. After the growth of a blue light emitting diode ... -
Excitation resolved color conversion of CdSe/ZnS core/shell quantum dot solids for hybrid white light emitting diodes
(American Institute of Physics, 2009-04-28)In this paper, for their use as nanoluminophors on color-conversion white light emitting diodes (LEDs), we present spectrally resolved relative quantum efficiency and relative color (photon) conversion efficiency of CdSe/ZnS ... -
Excitonic improvement of colloidal nanocrystals in salt powder matrix for quality lighting and color enrichment
(OSA - The Optical Society, 2016)Here we report excitonic improvement in color-converting colloidal nanocrystal powders enabled by co-integrating nonpolar greenand red-emitting nanocrystal energy transfer pairs into a single LiCl salt matrix. This leads ... -
Excitonically driven quantum dot light-emitting diodes: exLEDs
(Optical Society of America, 2013)A hybrid platform of colloidal quantum dots integrated into conjugated polymers is eported for excitonically driven light-emitting diodes having pure quantum dot emission in the electroluminescence spectrum with substantially ...
