Read by QxMD icon Read

Light-emitting diodes

Elisabeth Kreidt, Lorenzo Arrico, Francesco Zinna, Lorenzo Di Bari, Michael Seitz
Circularly polarised luminescence (CPL) is a chiroptical phenomenon gaining more and more attention, as the availability of the necessary spectrometers is getting better and first applications in bioimaging or for the preparation of OLEDs (organic light emitting diodes) are coming within range. Until now most examples of distinctly CPL-active compounds were europium and terbium complexes though theoretically the electronic structure of samarium should be as suitable as the one of terbium. This discrepancy can be accounted for by the high susceptibility of samarium to non-radiative deactivation processes...
June 21, 2018: Chemistry: a European Journal
Yatao Zou, Muyang Ban, Yingguo Yang, Sai Bai, Chen Wu, Yujie Han, Tian Wu, Yeshu Tan, Qi Huang, Xingyu Gao, Tao Song, Qiao Zhang, Baoquan Sun
Solution-processed perovskite light emitting diodes (LEDs) have attracted wide attentions in the past several years. However, the overall efficiency and stability of perovskite-based LEDs remains inferior to those of organic or quantum dot LEDs. Non-radiative charge recombination and the unbalanced charge injection are two critical factors that limit the device efficiency and operational stability of perovskite LEDs. Here, we develop a strategy to modify the interface between hole transport layer and the perovskite emissive layer with an amphiphilic conjugated polymer of poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN)...
June 21, 2018: ACS Applied Materials & Interfaces
Maria Aparecida Dos Santos Traverzim, Sergio Makabe, Daniela Fátima Teixeira Silva, Christiane Pavani, Sandra Kalil Bussadori, Kristianne Santos Porta Fernandes, Lara Jansiski Motta
BACKGROUND: Labor pain is one of the most intense pains experienced by women, which leads to an increase in the number of women opting to undergo a cesarean delivery. Pharmacological and nonpharmacological analgesia methods are used to control labor pain. Epidural analgesia is the most commonly used pharmacological analgesia method. However, it may have side effects on the fetus and the mother. Light-emitting diode (LED) photobiomodulation is an effective and noninvasive alternative to pharmacological methods...
June 2018: Medicine (Baltimore)
Keisuke Ikehata, Yuanyuan Zhao, Harshad Kulkarni, Yuan Li, Shane A Snyder, Kenneth P Ishida, Michael A Anderson
Reverse osmosis (RO)-based desalination and advanced water purification facilities have inherent challenges associated with concentrate management and disposal. Although enhanced permeate recovery and concentrate minimization are desired, membrane scaling due to inorganic constituents such as silica, calcium, phosphate, and iron hinders the process. To solve this problem, a new diatom-based photobiological process has been developed to remove these scaling constituents by biological uptake and precipitation...
June 19, 2018: Environmental Science & Technology
Qiang Su, Heng Zhang, Yizhe Sun, Xiao Wei Sun, Shuming Chen
The effect of post-annealing on the device characteristics is systematically investigated. The external quantum efficiency (EQE) of blue quantum-dot light-emitting diodes (QLEDs) is significantly improved from 5.22% to 9.81% after post-annealing. Similar results are obtained in green and red QLEDs, whose EQEs are enhanced from 11.47% and 13.60% to 15.57% and 16.59%, respectively. The annealed devices also exhibit larger current density. The origin of efficiency improvement is thoroughly investigated. Our finding indicates that post-annealing promotes the interfacial reaction of Al and ZnMgO, and consequently leads to the metallization of AlZnMgO contact and the formation of AlOx interlayer...
June 19, 2018: ACS Applied Materials & Interfaces
Changsu Lee, Joon-Woo Ahn, Jin-Baek Kim, Jee Young Kim, Yoon-E Choi
The unicellular green microalga Haematococcus pluvialis has the highest content of the natural antioxidant, astaxanthin. Previously, it was determined that astaxanthin accumulation in H. pluvialis could be induced by blue-wavelength irradiation; however, the molecular mechanism remains unknown. The present study aimed to compare the transcriptome of H. pluvialis, with respect to astaxanthin biosynthesis, under the monochromatic red (660 nm) or blue (450 nm) light-emitting diode (LED) irradiation. Among a total of 165,372 transcripts, we identified 67,703 unigenes, of which 2245 and 171 were identified as differentially expressed genes (DEGs) in response to blue and red irradiation, respectively...
June 18, 2018: World Journal of Microbiology & Biotechnology
Jason Lanoue, Evangelos D Leonardos, Bernard Grodzinski
Translocation of assimilates is a fundamental process involving carbon and water balance affecting source/sink relationships. Diurnal patterns of CO2 exchange, translocation (carbon export), and transpiration of an intact tomato source leaf were determined during 14 CO2 steady-state labeling under different wavelengths at three pre-set photosynthetic rates. Daily patterns showed that photosynthesis and export were supported by all wavelengths of light tested including orange and green. Export in the light, under all wavelengths was always higher than that at night...
2018: Frontiers in Plant Science
Alexandre F De Moraes Filho, Pedro M Gewehr, Joaquim M Maia, Douglas R Jakubiak
This paper presents a gaseous oxygen detection system based on time-resolved phosphorimetry (time-domain), which is used to investigate O2 optical transducers. The primary sensing elements were formed by incorporating iridium(III) and palladium(II) meso -tetrakis(pentafluorophenyl)porphyrin complexes (IrTFPP-CO-Cl and PdTFPP) in polystyrene (PS) solid matrices. Probe excitation was obtained using a violet light-emitting diode (LED) (low power), and the resulting phosphorescence was detected by a high-sensitivity compact photomultiplier tube...
June 15, 2018: Sensors
Zhibin Wang, Tai Cheng, Fuzhi Wang, Yiming Bai, Xingming Bian, Bing Zhang, Tasawar Hayat, Ahmed Alsaedi, Zhan'ao Tan
Stable and efficient red (R), green (G), and blue (B) light sources based on solution-processed quantum dots (QDs) play important roles in next-generation displays and solid-state lighting technologies. The brightness and efficiency of blue QDs-based light-emitting diodes (LEDs) remain inferior to their red and green counterparts, due to the inherently unfavorable energy levels of different colors of light. To solve these problems, a device structure should be designed to balance the injection holes and electrons into the emissive QD layer...
May 31, 2018: Journal of Visualized Experiments: JoVE
Hwansu Sim, Chanho Kim, Shingyu Bok, Min Ki Kim, Hwisu Oh, Guh-Hwan Lim, Sung Min Cho, Byungkwon Lim
Silver (Ag) nanowires (NWs) are promising building blocks for flexible transparent electrodes, which are key components in fabricating soft electronic devices such as flexible organic light emitting diodes (OLEDs). Typically, Ag NWs have been synthesized using a polyol method, but it still remains a challenge to produce high-aspect-ratio Ag NWs via a simple and rapid process. In this work, we developed a modified polyol method and newly found that the addition of propylene glycol to ethylene glycol-based polyol synthesis facilitated the growth of Ag NWs, allowing the rapid production of long Ag NWs with high aspect ratios of about 2000 in a high yield (∼90%) within 5 min...
June 18, 2018: Nanoscale
Luciana Gonçalves Langella, Heliodora Leão Casalechi, Shaiane Silva Tomazoni, Douglas Scott Johnson, Regiane Albertini, Rodney Capp Pallotta, Rodrigo Labat Marcos, Paulo de Tarso Camillo de Carvalho, Ernesto Cesar Pinto Leal-Junior
When conservative treatments fail, hip osteoarthritis (OA), a chronic degenerative disease characterized by cartilage wear, progressive joint deformity, and loss of function, can result in the need for a total hip arthroplasty (THA). Surgical procedures induced tissue trauma and incite an immune response. Photobiomodulation therapy (PBMt) using low-level laser therapy (LLLT) and/or light-emitting diode therapy (LEDT) has proven effective in tissue repair by modulating the inflammatory process and promoting pain relief...
June 16, 2018: Lasers in Medical Science
Po-Hsun Lei, Chyi-Da Yang, Yong-Sian Yang, Jian-Hong Lin
In this study, we synthesized a periodic polystyrene nanosphere (PS NS) array using the dip-drop method with post-deposition etching to improve the light extraction efficiency (LEE) of InGaN/GaN light-emitting diodes (LEDs). The dip-drop method has advantages such as simple procedure, inexpensive equipment, room temperature deposition, and easy implementation in LEDs. The arrangement of PS NSs on an indium-tin-oxide (ITO)-coated glass substrate depends on the average dip-drop speed and the concentration of the PS NS suspension...
June 15, 2018: Nanoscale Research Letters
Bo Wang, Congyang Zhang, Shouqiang Huang, Zhichun Li, Long Kong, Ling Jin, Junhui Wang, Kaifeng Wu, Liang Li
Lead halide perovskite nanocrystals (NCs) as promising optoelectronic materials are intensively researched. However, the instability is one of the biggest challenges needed to overcome before fulfill their practical applications. To improve their stability, we present a postsynthetic controlled phase transformation of CsPbBr3 toward CsPbBr3/Rb4PbBr6 core/shell structure triggered by rubidium oleate treatment. The resulted core/shell NCs show exceptional photostability both in solution and on-chip. The solution of CsPbBr3/Rb4PbBr6 NCs can remain over 90% of the initial emission photoluminescence quantum yields (PLQY) after 42 h of intense light-emitting diodes illumination (450 nm, 175 mW/cm2), which is even better than the conventional CdSe/CdS quantum dots whose emission drop to 50% after 18 h under the same condition...
June 15, 2018: ACS Applied Materials & Interfaces
Hyunkyung Lee, Yongxun Jin, Seungkwan Hong
Since ultraviolet light emitting diodes (UV-LEDs) have emerged as an alternative light source for UV disinfection systems, enhancement of reactor performance is a demanding challenge to promote its practical application in water treatment process. This study explored the underlying mechanism of the inefficiency observed in flow-through mode UV disinfection tests to improve the light utilization of UV-LED applications. In particular, the disinfection performance of UV-LED reactors was evaluated using two different flow channel types, reservoir and pathway systems, in order to elucidate the impact of physical circumstances on germicidal efficiency as the light profile was adjusted...
June 7, 2018: Journal of Photochemistry and Photobiology. B, Biology
Lei Wang, Zhaoxiang Dai, Rulong Zhou, Bingyan Qu, Xiao Cheng Zeng
Mn4+ doped phosphors, as an alternative to rare-earth element doped phosphors, have attracted immense attention owing to their ultrahigh quantum efficiency of red emission for potential applications in high rendering white LEDs (light-emitting diodes). Their performance can be largely affected by quenching phenomena such as thermal quenching, concentration quenching and the quenching induced by some intrinsic/extrinsic defects. However, the quenching mechanisms due to the defect levels and host band are still incompletely understood...
June 14, 2018: Physical Chemistry Chemical Physics: PCCP
Yang Wang, Adriana A Zekveld, Dorothea Wendt, Thomas Lunner, Graham Naylor, Sophia E Kramer
OBJECTIVES: Pupil light reflex (PLR) has been widely used as a method for evaluating parasympathetic activity. The first aim of the present study is to develop a PLR measurement using a computer screen set-up and compare its results with the PLR generated by a more conventional setup using light-emitting diode (LED). The parasympathetic nervous system, which is known to control the 'rest and digest' response of the human body, is considered to be associated with daily life fatigue. However, only few studies have attempted to test the relationship between self-reported daily fatigue and physiological measurement of the parasympathetic nervous system...
2018: PloS One
Chao Zhao, Mohamed Ebaid, Huafan Zhang, Davide Priante, Bilal Janjua, Daliang Zhang, Nini Wei, Abdullah A Alhamoud, Mohammad Khaled Shakfa, Tien Khee Ng, Boon S Ooi
p-Type doping in wide bandgap and new classes of ultra-wide bandgap materials has long been a scientific and engineering problem. The challenges arise from the large activation energy of dopants and high densities of dislocations in materials. We report here, a significantly enhanced p-type conduction using high-quality AlGaN nanowires. For the first time, the hole concentration in Mg-doped AlGaN nanowires is quantified. The incorporation of Mg into AlGaN was verified by correlation with photoluminescence and Raman measurements...
June 13, 2018: Nanoscale
Shujie Wang, Xiaoyu Dou, Ling Chen, Yan Fang, Aqiang Wang, Huaibin Shen, Zuliang Du
Extracting light from quantum dot light emitting diodes (QLEDs) by applying optical-functional nanostructures inside and outside the devices is essential for their commercial application in illumination and displays. In this paper, we demonstrate the highly effective extraction of waveguided light from the active region of QLEDs by embedding internal grating patterns fabricated using a nanoimprint lithography technique. The grating couples out waveguide mode power into the substrate without changing the device's electrical properties, resulting in an increase in both the external quantum efficiency and luminous efficiency for a green QLED from 11...
June 13, 2018: Nanoscale
L Thielemans, M Trip-Hoving, J Landier, C Turner, T J Prins, E M N Wouda, B Hanboonkunupakarn, C Po, C Beau, M Mu, T Hannay, F Nosten, B Van Overmeire, R McGready, V I Carrara
BACKGROUND: Indirect neonatal hyperbilirubinemia (INH) is a common neonatal disorder worldwide which can remain benign if prompt management is available. However there is a higher morbidity and mortality risk in settings with limited access to diagnosis and care. The manuscript describes the characteristics of neonates with INH, the burden of severe INH and identifies factors associated with severity in a resource-constrained setting. METHODS: We conducted a retrospective evaluation of anonymized records of neonates hospitalized on the Thai-Myanmar border...
June 12, 2018: BMC Pediatrics
Min Zhang, Binbin Hu, Lili Meng, Ruixin Bian, Siyuan Wang, Yunjun Wang, Huan Liu, Lei Jiang
Fabrication of a high quality quantum dots (QDs) film is essentially important for a high-performance QDs light emitting diode display (QLED) device. It is normally a high-cost and multiple-step solution transfer process where large amount of QDs was needed but with only limited useful. Thus, developing a simple, efficient and low-cost approach to fabricate high quality micro-patterned QDs film is urgently needed. Here, we proposed that the Chinese brush enables the controllable transfer of QDs solution directly into homogeneous and ultra-smooth micro-patterned film in one-step...
June 12, 2018: Journal of the American Chemical Society
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"