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https://www.readbyqxmd.com/read/28454483/efficient-carrier-injection-transport-relaxation-and-recombination-associated-with-a-stronger-carrier-localization-and-a-low-polarization-effect-of-nonpolar-m-plane-ingan-gan-light-emitting-diodes
#1
Fann-Wei Yang, Yu-Siang You, Shih-Wei Feng
Based on time-resolved electroluminescence (TREL) measurement, more efficient carrier injection, transport, relaxation, and recombination associated with a stronger carrier localization and a low polarization effect in a nonpolar m-plane InGaN/GaN light emitting diode (m-LED), compared with those in a polar c-LED, are reported. With a higher applied voltage in the c-LED, decreasing response time and rising time improve device performance, but a longer recombination time degrades luminescence efficiency. By using an m-LED with a stronger carrier localization and a low polarization effect, shorter response, rising, and recombination times provide more efficient carrier injection, transport, relaxation, and recombination...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28454047/use-of-light-emitting-diodes-leds-for-enhanced-lipid-production-in-micro-algae-based-biofuels
#2
Alifha Severes, Shashank Hegde, L D'Souza, Smitha Hegde
Microalgae are an alternative source for renewable energy to overcome the energy crises caused by exhaustion of fuel reserves. Algal biofuel technology demands a cost effective strategy for net profitable productivity. Inconsistent illumination intensities hinder microalgal growth. The light-utilizing efficiency of the cells is critical. Light scarcity leads to low production and high intensities cause photo-inhibition. We report effective usage of LEDs of different band wavelengths on the growth of microalgae in a closed, controlled environment to generate biomass and lipid yields...
April 20, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28448276/white-light-emission-of-monolithic-ingan-gan-grown-on-morphology-controlled-nanostructured-gan-templates
#3
Keun Man Song, Do Hyun Kim, Jong Min Kim, Chu-Young Cho, Jehyuk Choi, Ka Hee Kim, Jinsub Park, Hogyoung Kim
We demonstrated an InGaN/GaN-based, monolithic, white light-emitting diode (LED) without phosphors by using morphology-controlled active layers formed on multi-facet GaN templates containing polar and semipolar surfaces. The nanostructured surface morphology was controlled by changing the growth time, and distinct multiple photoluminescence peaks were observed at 360, 460, and 560 nm; these features were caused by InGaN/GaN-based multiple quantum wells (MQWs) on the nanostructured facets. The origin of each multi-peak was related to the different indium (In) compositions in the different planes of the quantum wells grown on the nanostructured GaN...
April 27, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28447691/enhanced-device-lifetime-of-double-heterojunction-nanorod-light-emitting-diodes
#4
Seong-Yong Cho, Nuri Oh, Sooji Nam, Yiran Jiang, Moonsub Shim
Colloidal quantum dots (QDs) are emerging as solution-processable, high-performance materials for light-emitting diodes (LEDs). Understanding the failure mechanism(s) is of both fundamental and practical importance, yet little is known of how QD-LEDs fail. Here, we have carried out accelerated device lifetime measurements on double heterojunction nanorod- (DHNR) and QD-LEDs. A common dependence of device lifetime on the initial driving voltage is observed over more than two orders of magnitude range in the initial luminance...
April 27, 2017: Nanoscale
https://www.readbyqxmd.com/read/28447450/band-bending-of-ga-polar-gan-interfaced-with-al2o3-through-ultraviolet-ozone-treatment
#5
Kwangeun Kim, Jae Ha Ryu, Jisoo Kim, Sang June Cho, Dong Liu, Jeongpil Park, In-Kyu Lee, Baxter Moody, Weidong Zhou, John Albrecht, Zhenqiang Ma
Understanding the band bending at the interface of GaN/dielectric under different surface treatment conditions is critically important for device design, device performance, and device reliability. The effects of ultraviolet/ozone (UV/O3) treatment of the GaN surface on the energy band bending of atomic-layer-deposition (ALD) Al2O3 coated Ga-polar GaN were studied. The UV/O3 treatment and post-ALD anneal can be used to effectively vary the band bending, valence band offset, conduction band offset, and interface dipole at the Al2O3/GaN interfaces...
April 27, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28447448/lanthanide-organic-gels-logs-as-a-multifunctional-supramolecular-smart-platform
#6
José Yago Rodrigues Silva, Leonis Lourenço da Luz, Filipe Gabriel Martinez Mauricio, Iane Bezerra Vasconcelos Alves, Jamylle Nunes de Souza Ferro, Emiliano Barreto, Ingrid Tavora Weber, Walter Mendes de Azevedo, Severino Alves Júnior
A multifunctional smart supramolecular platform based on a lanthanide-organic hydrogel is presented. This platform, which provides unique biocompatibility and tunable optical properties, is synthesized by a simple, fast and reproducible eco-friendly microwave-assisted route. Photoluminescent properties enable the production of coated light-emitting diodes (LED), unique luminescent barcodes dependent on the excitation wavelength and thin-films for use in tamper seals. Moreover, piroxicam entrapped in hydrogel acts as a transdermal drug release device efficient in inhibiting edemas compared to a commercial reference...
April 27, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28447446/highly-conductive-transparent-and-flexible-electrodes-including-double-stacked-thin-metal-films-for-transparent-flexible-electronics
#7
Jun Hee Han, Do-Hong Kim, Eun Gyo Jeong, Tae-Woo Lee, Myung Keun Lee, Jeong Woo Park, Hoseung Lee, Kyung Cheol Choi
In order to keep pace with the era of transparent and deformable electronics, the electrode functions should be improved. In this paper, an innovative structure is suggested to overcome the tradeoff between optical and electrical properties that commonly arises with transparent electrodes. The structure of double stacked metal films showed high conductivity (< 3 Ω/sq.) and high transparency (~90 %) simultaneously. A proper space between two metal films led to high transmittance by an optical phenomenon...
April 27, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28446682/smartphone-controlled-optogenetically-engineered-cells-enable-semiautomatic-glucose-homeostasis-in-diabetic-mice
#8
REVIEW
Jiawei Shao, Shuai Xue, Guiling Yu, Yuanhuan Yu, Xueping Yang, Yu Bai, Sucheng Zhu, Linfeng Yang, Jianli Yin, Yidan Wang, Shuyong Liao, Sanwei Guo, Mingqi Xie, Martin Fussenegger, Haifeng Ye
With the increasingly dominant role of smartphones in our lives, mobile health care systems integrating advanced point-of-care technologies to manage chronic diseases are gaining attention. Using a multidisciplinary design principle coupling electrical engineering, software development, and synthetic biology, we have engineered a technological infrastructure enabling the smartphone-assisted semiautomatic treatment of diabetes in mice. A custom-designed home server SmartController was programmed to process wireless signals, enabling a smartphone to regulate hormone production by optically engineered cells implanted in diabetic mice via a far-red light (FRL)-responsive optogenetic interface...
April 26, 2017: Science Translational Medicine
https://www.readbyqxmd.com/read/28445880/heating-of-newborn-infants-due-to-blue-light-emitting-diode-fibreoptic-phototherapy-pads
#9
Pei Ling Ng, Tony Carlisle, Marleesa Ly, Scott Adam Morris
BACKGROUND: Surface temperatures of fibreoptic phototherapy pads using a high intensity blue light-emitting diode (LED) light source have not been studied. OBJECTIVES: The aim of this study was to measure the temperature of LED fibreoptic phototherapy pads during phototherapy in a bench-top study, and to determine temperature effects on babies during phototherapy. METHODS: A commercially available LED fibreoptic phototherapy system was tested...
April 27, 2017: Neonatology
https://www.readbyqxmd.com/read/28443899/the-role-of-sulfur-oxidation-in-controlling-the-electronic-properties-of-sulfur-containing-host-molecules-for-phosphorescent-organic-light-emitting-diodes
#10
E Varathan, V Subramanian
In this study a series of dibenzothiophene (DBT) derivatives having different valence states of sulfur atoms have been reported as host materials for blue phosphorescent organic light-emitting diodes. Their electronic properties have also been thoroughly investigated to develop structure-property relationships which include the consideration of the effect of various oxidation states of the sulfur atom in the core moiety and linking (C-N linkage) of subunits with the core at different positions. The results obtained from the electronic structure calculations highlight that the triplet energy (ET), singlet-triplet energy difference (ΔEST), reorganization energy for the hole and the injection barrier for the electron decrease with an increase in the oxidation state of the sulfur atom in DBT...
April 26, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28441144/highly-efficient-inverted-organic-light-emitting-diodes-by-inserting-zinc-oxide-polyethyleneimine-zno-pei-nano-composite-interfacial-layer
#11
Rifat Kaçar, Selin Mucur, Fikret Yildiz, Salih Dabak, Emine Tekin
The electrode/organic interface is one of the crucial key factor to attain superior device performance in organic electronics, and inserting a tailor-made layer can dramatically modify its properties. Using of nano-composite (NC) materials lead to many advantages by combining the materials with the objective of getting desirable combination of properties. In this context, zinc oxide/polyethyleneimine (ZnO:PEI) NC film was incorporated as the interfacial layer into the inverted bottom-emission organic light emitting diodes (IBOLEDs) and fully optimized...
April 25, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28441021/photophysical-and-electroluminescent-properties-of-ptag2-acetylide-complexes-supported-with-meso-and-rac-tetraphosphine
#12
Hui-Xing Shu, Jin-Yun Wang, Qian-Chong Zhang, Zhong-Ning Chen
1,2-Bis[[(diphenylphosphino)methyl](phenyl)phosphino]ethane (dpmppe) was prepared as a new tetraphosphine, and the corresponding rac and meso stereoisomers were successfully separated in view of their solubility difference in acetone. The substitution of PPh3 into Pt(PPh3)2(C≡CR)2 (R = aryl) with rac- or meso-dpmppe gives Pt(rac-dpmppe)(C≡CR)2 or Pt(meso-dpmppe)(C≡CR)2, respectively. Using Pt(rac-dpmppe)(C≡CR)2 or Pt(meso-dpmppe)(C≡CR)2 as a precursor, PtAg2 heterotrinuclear cluster complexes were synthesized and characterized by X-ray crystallography...
April 25, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28439118/white-light-emitting-diodes-stabilizing-colour-and-intensity
#13
Philippe F Smet, Jonas J Joos
No abstract text is available yet for this article.
April 25, 2017: Nature Materials
https://www.readbyqxmd.com/read/28438153/damage-to-the-macula-associated-with-led-derived-blue-laser-exposure-a-case-report
#14
Lingling Liang, Zhihua Cui, Chengwei Lu, Qian Hao, Yajuan Zheng
BACKGROUND: Light emitting diodes laser is emerging as an important source of light replacing conventional lights. It is widely used for illumination in the bar where young people love to go. But not everyone knows about the light damage to the eye especially to the macula. In this article, we report the case of a macular damage induced by LED-derived blue laser in a bar, studied with optical coherence tomography (OCT) to evaluate the retinal lesion and multifocal electroretinography (mfERG) to evaluate functional damage...
April 24, 2017: BMC Ophthalmology
https://www.readbyqxmd.com/read/28437997/effect-of-zno-nanostructures-on-the-optical-properties-of-white-light-emitting-diodes
#15
Longshi Rao, Yong Tang, ZongTao Li, Xinrui Ding, Jiasheng Li, Shudong Yu, Caiman Yan, Hangaung Lu
White light produced by blue LEDs with yellow phosphor is the most widely used methods, but it results in poor quality in angular CCT uniformity. In this work, a novel technique was introduced to solve this problem by integrating different ZnO nanostructures into white light-emitting diodes. The experiment of ZnO doped films and the simulation of Finite-Difference Time-Domain (FDTD) were carried out. The result indicated scattering effect of ZnO nanoparticles could improve uniformity of scattering energy effectively...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437924/synthesis-and-luminescence-properties-of-ba-sub-3-sub-lu-po-sub-4-sub-sub-3-sub-sm-sup-3-sup-phosphor-for-white-light-emitting-diodes
#16
Zaifa Yang, Denghui Xu, Jiayue Sun
A series of Ba<sub>3</sub>Lu(PO<sub>4</sub>)<sub>3</sub>:Sm<sup>3+</sup> phosphors were prepared by traditional high temperature solid-state reaction methods. The site-preferred occupancy of Sm<sup>3+</sup> in Ba<sub>3</sub>Lu(PO<sub>4</sub>)<sub>3</sub> and the luminescence properties of Ba<sub>3</sub>Lu(PO<sub>4</sub>)<sub>3</sub>:Sm<sup>3+</sup> were studied combined with X-ray diffraction, photoluminescence excitation (PLE) spectra, and emission (PL) spectra as well as temperature-dependent PL and decay curves...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28437251/solution-processible-moo-sub-x-sub-incorporated-graphene-anode-for-efficient-polymer-light-emitting-diodes
#17
Dongchan Lee, Donghyuk Kim, Yonghee Lee, Duk Young Jeon
Graphene has attracted great attention owing to its superb properties as an anode of organic or polymer light-emitting diodes (OLEDs or PLEDs). However, there are still barriers for graphene to replace existing indium tin oxide (ITO) due to relatively high sheet resistance and workfunction mismatch. In this study, PLEDs using molybdenum oxide (MoO<sub>x</sub>) nanoparticle-doped graphene are demonstrated on a plastic substrate to have a low sheet resistance and a high workfunction. Also, this work shows how the doping amount influence on electronic properties of graphene anode and the PLED performance...
April 24, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28436573/mapping-energy-levels-for-organic-heterojunctions
#18
Yiying Li, Peicheng Li, Zheng-Hong Lu
An organic semiconductor thin film is a solid-state matter comprising one or more molecules. For applications in electronics and photonics, several distinct functional organic thin films are stacked together to create a variety of devices such as organic light-emitting diodes and organic solar cells. The energy levels at these thin-film junctions dictate various electronic processes such as the charge transport across these junctions, the exciton dissociation rates at donor-acceptor molecular interfaces, and the charge trapping during exciton formation in a host-dopant system...
April 24, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28436501/bis-zn-ii-salphen-complexes-bearing-pyridyl-functionalized-ligands-for-efficient-organic-light-emitting-diodes-oleds
#19
Jiang Zhao, Feifan Dang, Boao Liu, Yong Wu, Xiaolong Yang, Guijiang Zhou, Zhaoxin Wu, Wai-Yeung Wong
Inspired by the emissive features of Zn(II) complexes based on bis-Schiff base ligands, bis-Zn(II) salphen complexes bearing pyridyl functionalized ligands have been successfully synthesized. Their photophysical features, electrochemical behavior and electroluminescent (EL) properties have been investigated in detail. The functionalized bis-Zn(II) salphen complexes can exhibit high thermal stability up to 417 °C, and their photoluminescence (PL) spectra show a maximal emission wavelength peak at ca. 565 nm both in solution and PMMA doped films...
April 24, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28436499/white-light-emission-with-tuneable-colour-temperature-and-high-colour-rendering-index-from-cds-si-multi-interface-nanoheterojunctions
#20
Yong Li, Yue Li Song, Peng Fei Ji, Feng Qun Zhou
CdS/Si multi-interface nanoheterojunctions (CdS/Si-NPA) were fabricated by depositing CdS nanocrystallites (nc-CdS) on silicon nanoporous pillar arrays (Si-NPA) by chemical bath deposition. White electroluminescence (EL) with a high colour rendering index from a prototypical light emitting diode based on CdS/Si-NPA has been reported, which does not need complex colour mixing or conversion techniques. The white EL can be composed into three primary colours, which include blue emissions from the Si-NPA, the green emissions from the bandgap emission of nc-CdS and red emissions from the defects in the nc-CdS...
April 24, 2017: Nanoscale
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