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https://www.readbyqxmd.com/read/29149083/co-precipitation-synthesis-and-optical-properties-of-mn-4-doped-hexafluoroaluminate-w-led-phosphors
#1
Tim Senden, Robin G Geitenbeek, Andries Meijerink
Mn(4+)-activated hexafluoroaluminates are promising red-emitting phosphors for white light emitting diodes (w-LEDs). Here, we report the synthesis of Na₃AlF₆:Mn(4+), K₃AlF₆:Mn(4+) and K₂NaAlF₆:Mn(4+) phosphors through a simple two-step co-precipitation method. Highly monodisperse large (~20 μm) smoothed-octahedron shaped crystallites are obtained for K₂NaAlF₆:Mn(4+). The large size, regular shape and small size distribution are favorable for application in w-LEDs. All Mn(4+)-doped hexafluoroaluminates show bright red Mn(4+) luminescence under blue light excitation...
November 17, 2017: Materials
https://www.readbyqxmd.com/read/29148804/a-nanobionic-light-emitting-plant
#2
Seon-Yeong Kwak, Juan Pablo Giraldo, Min Hao Wong, Volodymyr Koman, Tedrick Lew, Jon Ell, Mark Weidman, Rosalie Sinclair, Markita P Landry, William A Tisdale, Michael S Strano
The engineering of living plants for visible light emission and sustainable illumination is compelling because plants possess independent energy generation and storage mechanisms and autonomous self-repair. Herein, we demonstrate a plant nanobionic approach that enables exceptional luminosity and lifetime utilizing four chemically-interacting nanoparticles, including firefly luciferase conjugated silica (SNP-Luc), D-luciferin releasing poly(lactic-co-glycolic acid) (PLGA-LH2), coenzyme A functionalized chitosan (CS-CoA) and semiconductor nanocrystal phosphors for longer wavelength modulation...
November 17, 2017: Nano Letters
https://www.readbyqxmd.com/read/29148706/porous-carbon-with-willow-leaf-shaped-pores-for-high-performance-supercapacitors
#3
Yanhong Shi, Lin-Lin Zhang, Tyler B Schon, Huan-Huan Li, Chao-Ying Fan, Xiao-Ying Li, Hai-Feng Wang, Xing-Long Wu, Haiming Xie, Haizhu Sun, Dwight S Seferos, Jingping Zhang
A novel kind of biomass-derived high oxygen containing carbon materials doped with nitrogen that have willow leaf shaped pores was synthesized. The obtained carbon materials have an exotic hierarchical pore structure composed of bowl shaped macropores, willow leaf shaped pores, and an abundance of micropores. This unique hierarchical porous structure provides an effective combination of high current densities with high capacitance due to a pseudocapacitive component that is afforded by the introduction of nitrogen and oxygen dopants...
November 17, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29144119/self-assembly-driven-aggregation-induced-emission-of-copper-nanoclusters-a-novel-technology-for-lighting
#4
Yi Liu, Dong Yao, Hao Zhang
Because of the specific properties including HOMO-LUMO electronic transition, size-dependent fluorescent emission, and intense light absorption, metal nanoclusters (NCs) have been considered to be one of the most competitive color conversion materials in light-emitting diodes (LEDs). However, the monotonous emission color and the low emission stability and intensity of individual metal NCs strongly limit their universal application. Inspired by the concept of "aggregation-induced emission" (AIE), the utilization of highly ordered metal NC assemblies opens a door to resolve these problems...
November 16, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29143003/a-mixed-dimensional-light-emitting-diode-based-on-a-p-mos2-nanosheet-and-an-n-cdse-nanowire
#5
Pan Li, Kai Yuan, Der-Yuh Lin, Xiaolong Xu, Yilun Wang, Yi Wan, Haoran Yu, Kun Zhang, Yu Ye, Lun Dai
The construction of the mixed-dimensional van der Waals (vdW) heterostructures with two-dimensional (2D) and one-dimensional (1D) materials can advantageously integrate their respective dimensional properties to produce new device functionalities and/or enhance device performance. In this case, a single semiconductor nanowire (NW) can function as an optical cavity and a gain medium, while the atomically thin 2D material does not strongly absorb the NW's light emission or disturb the optical propagation mode...
November 16, 2017: Nanoscale
https://www.readbyqxmd.com/read/29140683/nanocomposite-phosphor-consisting-of-cai2-eu-2-single-nanocrystals-embedded-in-crystalline-sio2
#6
Hisayoshi Daicho, Takeshi Iwasaki, Yu Shinomiya, Akitoshi Nakano, Hiroshi Sawa, Wataru Yamada, Satoru Matsuishi, Hideo Hosono
High luminescence efficiency is obtained in halide- and chalcogenide-based phosphors, but they are impractical because of their poor chemical durability. Here we report a halide-based nanocomposite phosphor with excellent luminescence efficiency and sufficient durability for practical use. Our approach was to disperse luminescent single nanocrystals of CaI2:Eu(2+) in a chemically stable, translucent crystalline SiO2 matrix. Using this approach, we successfully prepared a nanocomposite phosphor by means of self-organization through a simple solid-state reaction...
November 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29140080/vapor-assisted-solution-approach-for-high-quality-perovskite-ch3nh3pbbr3-thin-films-for-high-performance-green-light-emitting-diodes-applications
#7
Huifang Ji, Zhifeng Shi, Xuguang Sun, Ying Li, Sen Li, Lingzhi Lei, Di Wu, Tingting Xu, Xinjian Li, Guotong Du
Vapor-assisted solution method was developed to prepare the high-quality organic-inorganic halide perovskite CH3NH3PbBr3 (MAPbBr3) thin films. We detailedly investigated the effect of evaporation time and temperature of MABr powder on the microstructure, crystallinity and optical characterizations of MAPbBr3 thin films, and a controllable morphology evolution with varying surface coverage was observed. Temperature-dependent and time-resolved photoluminescence (PL) measurements were carried out to investigate the optical transition mechanisms and carrier recombination dynamics of MAPbBr3 thin films...
November 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29139000/effect-of-light-polarization-on-the-efficiency-of-photodynamic-therapy-of-basal-cell-carcinomas-an-in-vitro-cellular-study
#8
M JalalKamali, S N Nematollahi-Mahani, M Shojaei, A Shamsoddini, N Arabpour
In an in vitro study, the effect of light polarization on the efficiency of 5-aminolaevulinic acid (ALA) photodynamic therapy (PDT) of basal cell carcinoma (BCC) was investigated. Three states of light polarization (non-polarized, linearly polarized, and circularly polarized) were considered. Cells were exposed to green (532 pm 20 nm) irradiation from light emitting diodes. Cell survival was measured by the colorimetric assay (WST-1) and Trypan blue staining. The colorimetric assay showed a pronounced decrease in the cell viability (up to 30%) using polarized light compared to the non-polarized one in the wavelength region used...
November 15, 2017: Lasers in Medical Science
https://www.readbyqxmd.com/read/29138778/dual-phosphorescence-emission-of-dinuclear-platinum-ii-complex-incorporating-cyclometallating-pyrenyl-dipyridine-based-ligand-and-its-application-in-near-infrared-solution-processed-polymer-light-emitting-diodes
#9
Zhaoran Hao, Fanyuan Meng, Pu Wang, Yafei Wang, Hua Tan, Yong Pei, Shijian Su, Yu Liu
Two novel mono- and binuclear cyclometalated platinum(ii) complexes of (BuPyrDPy)Pt(dpm) and (BuPyrDPy)[Pt(dpm)]2 incorporating a pyrenyl-dipyridine-based cyclometalated ligand were synthesized and characterized, respectively. Single-crystal X-ray diffraction of the two materials revealed each complex's coordination mode; their photophysical, electrochemical as well as electroluminescent properties were also investigated. Both complexes exhibited good solubility and excellent thermal stability. (BuPyrDPy)[Pt(dpm)]2 presented dual phosphorescence emissive character at room-temperature and showed an increased quantum efficiency compared to that of (BuPyrDPy)Pt(dpm)...
November 15, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29137200/a-lab-on-a-chip-based-non-invasive-optical-sensor-for-measuring-glucose-in-saliva
#10
Dong Geon Jung, Daewoong Jung, Seong Ho Kong
A lab-on-a-chip (LOC)-based non-invasive optical sensor for measuring glucose in saliva was fabricated. Existing glucose sensors utilizing blood require acquisition of a blood sample by pricking the finger, which is painful and inconvenient. To overcome these limitations, we propose a non-invasive glucose sensor with LOC, micro-electro-mechanical system and optical measurement technology. The proposed sensor for measuring glucose in saliva involves pretreatment, mixing, and measurement on a single tiny chip...
November 13, 2017: Sensors
https://www.readbyqxmd.com/read/29136839/chromisense-a-colourimetric-lab-on-a-disc-sensor-for-chromium-speciation-in-water
#11
G Duffy, I Maguire, Brendan Heery, Pauline Gers, J Ducrée, F Regan
The development of a centrifugal device for quantitative analysis of both chromium (III) and (VI) species in water is reported. ChromiSense is a colourimetric sensor system that has been applied to the measurement of chromium in spiked river water samples. For analysis, the sample is loaded into a reservoir on the disposable microfluidic disc, along with reagents. A centrifugal force is created by spinning the disc to pump liquids through microchannels, causing them to mix and react to form a coloured product...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136828/compact-detectors-made-of-paired-leds-for-photometric-and-fluorometric-measurements-on-paper
#12
Marta Fiedoruk-Pogrebniak, Mateusz Granica, Robert Koncki
The utility of strikingly simple and cheap optoelectronic detectors operating according to a Paired-Emitter-Detector-Diode (PEDD) principle for microfluidic paper-based analytical devices (μPAD) has been experimentally confirmed. The prototypes of these compact detectors have been made of only two customary light emitting diodes without any additional optical parts like lens, filters, fibers etc. Moreover, for their operation economic and portable equipment is required (low-power circuit and ordinary voltmeter)...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136460/graphitic-nitrogen-triggers-red-fluorescence-in-carbon-dots
#13
Katerina Hola, Mária Sudolská, Sergii Kalytchuk, Dana Nachtigallova, Andrey L Rogach, Michal Otyepka, Radek Zbořil
Carbon dots (CDs) are a stable and highly biocompatible fluorescent material offering great application potential in cell labeling, optical imaging, LED diodes, and optoelectronic technologies. Because their emission wavelengths provide the best tissue penetration, red-emitting CDs are of a particular interest for applications in biomedical technologies. Current synthetic strategies enabling red-shifted emission include increasing the CD particle size (sp2 domain) by a proper synthetic strategy and tuning the surface chemistry of CDs with suitable functional groups (e...
November 14, 2017: ACS Nano
https://www.readbyqxmd.com/read/29134807/a-high-time-resolution-optical-sensor-for-monitoring-atmospheric-nitrogen-dioxide
#14
Yong Tian, Xiaomin Zhang, Hui-Yan Shen, Aifeng Liu, Zongshan Zhao, Ming-Li Chen, Xuwei Chen
High-time resolution monitoring nitrogen dioxide (NO2) is of great importance for studying the formation mechanism of aerosol and improving air quality. Based on the Griess-Saltzman (GS) reaction, a portable NO2 optical sensor was developed by employing a porous polypropylene membrane tube (PPMT) integrated gas permeation collector and detector. The PPMT was filled with GS reagents and covered with a coaxial jacket tube for gas collection. Its two ends were respectively fixed with a yellowish green light emitting diode and a photodiode for optic signal reception...
November 14, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29134402/modification-in-oxidative-processes-in-muscle-tissues-exposed-to-laser-and-light-emitting-diode-radiation
#15
Victor A Monich, Anna P Bavrina, Svetlana L Malinovskaya
Exposure of living tissues to high-intensity red or near-infrared light can produce the oxidative stress effects both in the target zone and adjacent ones. The protein oxidative modification (POM) products can be used as reliable and early markers of oxidative stress. The contents of modified proteins in the investigated specimens can be evaluated by the 2,4-dinitrophenylhydrazine assay (the DNPH assay). Low-intensity red light is able to decrease the activity of oxidative processes and the DNPH assay data about the POM products in the biological tissues could show both an oxidative stress level and an efficiency of physical agent protection against the oxidative processes...
November 13, 2017: Lasers in Medical Science
https://www.readbyqxmd.com/read/29134214/aggregation-induced-emission-assembled-ultrathin-films-for-white-light-emitting-diodes
#16
Zekun Zhang, Rui Tian, Wenjuan Zhou, Yanjun Lin, Chao Lu
Avoiding the intractable aggregation-caused quenching in solid-state materials, two aggregation-induced emission molecules were first implemented to fabricate white-light emitting ultrathin films with boosted quantum yields via layer-by-layer assembly. Such an ultrathin film-coated white light-emitting diode exhibits color purity.
November 14, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/29131980/pedestrians-perception-and-response-towards-vehicles-during-road-crossing-at-nighttime
#17
Venkatesh Balasubramanian, Rahul Bhardwaj
Pedestrian being involved in road traffic accidents (RTA) is about 22% of all road traffic related deaths. In this study, we have estimated the pedestrian's response towards an approaching vehicle and the time taken to correctly recognize it while they crossed the road in dim-light nighttime conditions. This is also extendable to cycles and other low powered vehicles. Thirty volunteers participated in this study. A collection of six videos, which comprised of different vehicle scenarios were shown to each of the participants...
November 10, 2017: Accident; Analysis and Prevention
https://www.readbyqxmd.com/read/29131369/photobiomodulation-for-traumatic-brain-injury-and-stroke
#18
REVIEW
Michael R Hamblin
There is a notable lack of therapeutic alternatives for what is fast becoming a global epidemic of traumatic brain injury (TBI). Photobiomodulation (PBM) employs red or near-infrared (NIR) light (600-1100nm) to stimulate healing, protect tissue from dying, increase mitochondrial function, improve blood flow, and tissue oxygenation. PBM can also act to reduce swelling, increase antioxidants, decrease inflammation, protect against apoptosis, and modulate microglial activation state. All these mechanisms of action strongly suggest that PBM delivered to the head should be beneficial in cases of both acute and chronic TBI...
November 13, 2017: Journal of Neuroscience Research
https://www.readbyqxmd.com/read/29130308/highly-enhanced-light-outcoupling-efficiency-in-ito-free-organic-light-emitting-diodes-using-surface-nanostructure-embedded-high-refractive-index-polymers
#19
Dong Woo Kim, Joo Won Han, Kwon Taek Lim, Yong Hyun Kim
We develop the internal light outcoupling system (HRLOC) based on the high refractive index polyimide (PI) and metal oxide nanoparticles for organic light-emitting diodes (OLEDs) with silver nanowires (AgNWs). The spontaneously formed nano-bump structures, high refractive index, and light scattering properties of HRLOC significantly enhance the light extraction efficiency of OLEDs. Not only do the outcoupling structures improve the light extraction efficiency, but remarkably enhance the electrical properties of OLEDs...
November 13, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29128218/exposure-to-light-emitting-diodes-may-be-more-damaging-to-the-sensory-properties-of-fat-free-milk-than-exposure-to-fluorescent-light
#20
Ana C Chang, Robin Dando
Light exposure can damage the sensory properties of milk, leading to adverse consumer responses. This is presumed to be through the action of photosensitive compounds such as riboflavin, present in milk and capable of releasing energy when irradiated, leading to damage of proteins and fats in the milk. Light-emitting diode (LED) lighting is assumed to be less damaging to milk, due to lower inherent power consumption. In this study, fat-free milk was exposed to LED and fluorescent light at 2,000 lx to compare the sensory thresholds of exposure, the flavor profile of milk produced by these exposures, and resultant consumer acceptance of the samples...
November 8, 2017: Journal of Dairy Science
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