Light-Emitting Diodes (LEDs): An Artificial Lighting Source for Biological Studies

2010 ◽  
pp. 134-139 ◽  
Author(s):  
Duong Tan Nhut ◽  
Nguyen Ba Nam
Keyword(s):  
Light Emitting Diodes ◽  
Light Emitting ◽  
Artificial Lighting ◽  
Biological Studies

scholarly journals A dual-emitting core–shell carbon dot–silica–phosphor composite for LED plant grow light

RSC Advances ◽  
2017 ◽  
Vol 7 (27) ◽  
pp. 16662-16667 ◽  
Author(s):  
Li Wang ◽  
Haoran Zhang ◽  
Xiaohua Zhou ◽  
Yingliang Liu ◽  
Bingfu Lei
Keyword(s):  
Disease Prevention ◽  
Plant Growth ◽  
Light Emitting Diodes ◽  
Core Shell ◽  
Carbon Dot ◽  
Light Emitting ◽  
Artificial Lighting

Light-emitting diodes (LEDs) are widely used for artificial lighting in plant factories and have been applied for disease prevention and for accelerating plant growth.

scholarly journals Design of highly efficient phosphor-converted white light-emitting diodes with color rendering indices (R1 − R15) ≥ 95 for artificial lighting

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yong Nam Ahn ◽  
Kyu Do Kim ◽  
Gopinathan Anoop ◽  
Gab Soo Kim ◽  
Jae Soo Yoo
Keyword(s):  
Light Source ◽  
White Light ◽  
Light Emitting Diodes ◽  
Light Sources ◽  
High Definition ◽  
Light Emitting ◽  
Artificial Lighting ◽  
Red Phosphors ◽  
White Light Emitting Diodes ◽  
Color Rendering

AbstractPhosphor-converted white light-emitting diodes (pc-WLEDs) are excellent energy-efficient light sources for artificial lighting applications. One goal of artificial lighting is to make objects/images look natural – as they look under the sunlight. The ability of a light source to accurately render the natural color of an object is gauged by the parameter – color rendering index (CRI). A conventional pc-WLED has an average CRI ~ 80, which is very low for accurate color reproduction. To utilize the pc-WLEDs for artificial lighting applications, all the CRI points (R1 – R15) should be above 95. However, there is a trade-off between CRI and luminous efficacy (LER), and it is challenging to increase both CRI and LER. Herein we propose a novel LED package (PKG) design to achieve CRI points ≥95 and efficiency ~100 lm/W by introducing two blue LEDs and a UV LED in combination with green and red phosphors. The silicone encapsulant, the current through the LEDs, and the green/red phosphor ratio were optimized for achieving high CRI and LER. Our re-designed LED PKG will find applications in stadium lighting as well as for ultra-high-definition television production where high CRI points are required for the artificial light source.

Injecting Inter-Layers and the Built-in Potential of Blue Polymer Light-Emitting Diodes

2000 ◽  
Vol 660 ◽  
Author(s):  
Thomas M. Brown ◽  
Ian S. Millard ◽  
David J. Lacey ◽  
Jeremy H. Burroughes ◽  
Richard H. Friend ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Light Emitting Diodes ◽  
Basic Structure ◽  
Thin Layers ◽  
Carrier Injection ◽  
Semiconducting Polymer ◽  
Light Emitting ◽  
Physical Mechanisms ◽  
Organic Solid ◽  
Polymer Light Emitting Diodes

ABSTRACTThe semiconducting-polymer/injecting-electrode heterojunction plays a crucial part in the operation of organic solid state devices. In polymer light-emitting diodes (LEDs), a common fundamental structure employed is Indium-Tin-Oxide/Polymer/Al. However, in order to fabricate efficient devices, alterations to this basic structure have to be carried out. The insertion of thin layers, between the electrodes and the emitting polymer, has been shown to greatly enhance LED performance, although the physical mechanisms underlying this effect remain unclear. Here, we use electro-absorption measurements of the built-in potential to monitor shifts in the barrier height at the electrode/polymer interface. We demonstrate that the main advantage brought about by inter-layers, such as poly(ethylenedioxythiophene)/poly(styrene sulphonic acid) (PEDOT:PSS) at the anode and Ca, LiF and CsF at the cathode, is a marked reduction of the barrier to carrier injection. The electro- absorption results also correlate with the electroluminescent characteristics of the LEDs.

Low-Temperature Operation of Green, Blue and UV InGaN/GaN Multiple-Quantum-Well Light-Emitting Diodes

2003 ◽  
Vol 764 ◽  
Author(s):  
X. A. Cao ◽  
S. F. LeBoeuf ◽  
J. L. Garrett ◽  
A. Ebong ◽  
L. B. Rowland ◽  
...  
Keyword(s):  
Quantum Well ◽  
Light Emitting Diodes ◽  
Multiple Quantum Well ◽  
Light Output ◽  
Localized States ◽  
Multiple Quantum ◽  
Nonradiative Recombination ◽  
Light Emitting ◽  
Temperature Range ◽  
Green Leds

Absract:Temperature-dependent electroluminescence (EL) of InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) with peak emission energies ranging from 2.3 eV (green) to 3.3 eV (UV) has been studied over a wide temperature range (5-300 K). As the temperature is decreased from 300 K to 150 K, the EL intensity increases in all devices due to reduced nonradiative recombination and improved carrier confinement. However, LED operation at lower temperatures (150-5 K) is a strong function of In ratio in the active layer. For the green LEDs, emission intensity increases monotonically in the whole temperature range, while for the blue and UV LEDs, a remarkable decrease of the light output was observed, accompanied by a large redshift of the peak energy. The discrepancy can be attributed to various amounts of localization states caused by In composition fluctuation in the QW active regions. Based on a rate equation analysis, we find that the densities of the localized states in the green LEDs are more than two orders of magnitude higher than that in the UV LED. The large number of localized states in the green LEDs are crucial to maintain high-efficiency carrier capture at low temperatures.

Blue light emitting diodes cripple Helicobacter pylori by targeting its virulence factors

2019 ◽  
Vol 65 (3) ◽  
Author(s):  
Homa Darmani ◽  
Ehda Am Smadi ◽  
Sereen Mb Bataineh
Keyword(s):  
Helicobacter Pylori ◽  
Blue Light ◽  
Virulence Factors ◽  
Light Emitting Diodes ◽  
Light Emitting
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