Syntheses, crystal structures and photoluminescence properties of Ca9Y(PO4)5(SiO4)F1.5O0.25:Ln3+ (Ln3+ = Eu3+/Tb3+/Dy3+/Sm3+) phosphors for near-UV white LEDs

RSC Advances ◽  
2016 ◽  
Vol 6 (95) ◽  
pp. 92371-92377 ◽  
Author(s):  
Man Liu ◽  
Wei Lü ◽  
Jiansheng Huo ◽  
Baiqi Shao ◽  
Yang Feng ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Red Light ◽  
Photoluminescence Properties ◽  
Light Emitting ◽  
White Leds ◽  
Red Led

We report red light-emitting Ca9Y(PO4)5(SiO4)F1.5O0.25:Eu3+/Sm3+ phosphors for the fabrication of red LED devices.

scholarly journals Critical Photoperiod and Optimal Quality of Night Interruption Light for Runner Induction in June-Bearing Strawberries

Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1996
Author(s):  
Yali Li ◽  
Jie Xiao ◽  
Jiangtao Hu ◽  
Byoung Ryong Jeong
Keyword(s):  
Red Light ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Light Emitting ◽  
Red Led ◽  
Critical Photoperiod ◽  
Closed Walk ◽  
White Light Emitting Diodes ◽  
Optimal Quality

The optimal photoperiod and light quality for runner induction in strawberries ‘Sulhyang’ and ‘Maehyang’ were investigated. Two experiments were carried out in a semi-closed walk-in growth chamber with 25/15 °C day/night temperatures and a light intensity of 250 μmol·m–2·s–1photosynthetic photon flux density (PPFD) provided from white light-emitting diodes (LEDs). In the first experiment, plants were treated with a photoperiod of either 12, 14, 16, 18, 20, or 22 h In the second experiment, a total of 4 h of night interruption (NI) light at an intensity of 70 μmol·m–2·s–1PPFD provided from either red, blue, green, white, or far-red LED in addition to 11 h short day (SD). The results showed that both ‘Sulhyang’ and ‘Maehyang’ produced runners when a photoperiod was longer than 16 h, and the number of runners induced positively correlated with the length of photoperiod. However, the plant growth, contents of chlorophyll, sugar and starch, and Fv/Fo decreased in a 22 h photoperiod. All qualities of the NI light, especially red light, significantly increased the number of runners and daughter plants induced per plant as compared with those in the SD treatment in both cultivars. In a conclusion, a photoperiod between 16 and 20 h and NI light, especially red NI light, can be used for quality runner induction in both ‘Sulhyang’ and ‘Maehyang’.

Growth and Light Properties of Fluorescent SiC for White LEDs

2012 ◽  
Vol 717-720 ◽  
pp. 87-92
Author(s):  
Mikael Syväjärvi ◽  
Rositza Yakimova ◽  
Motoaki Iwaya ◽  
Tetsuya Takeuchi ◽  
Isamu Akasaki ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
White Light ◽  
Energy Savings ◽  
Red Light ◽  
Visible Range ◽  
White Led ◽  
Light Emitting ◽  
Blue Led ◽  
White Leds ◽  
New Type

The LED technology started to developed many years ago with red light emitting diodes. To achieve the blue LED, novel growth technologies and process steps were explored, and made it possible to demonstrate efficient blue LED performance from nitrides. The efficiency was further developed and blue LEDs were commercially introduced in the 1990’s. The white LED became possible by the use of the blue LED and a phosphor that converts a part of the blue light to other colors in the visible range to combine into white light. However, even today there are limitations in the phosphor-based white LED technology, in particular for general lighting, and new solutions should be explored to speed the pace when white LEDs will be able to make substantial energy savings. In this paper we overview gallium nitride materials evolution and growth concepts for LEDs. We describe the fluorescent silicon carbide material prepared by a novel growth technology for a new type of white LED in general lighting with pure white light. This paper introduces an interesting research in fundamental growth and optical properties of light emitting silicon carbide.

Fundamentals and Applications of Red Light-Emitting Diodes (LEDs) In Vitro Plant Growth on Tomato Lycopersicon esculentum Mill

2019 ◽  
Vol 805 ◽  
pp. 141-145
Author(s):  
Nguyen Phuc Thien
Keyword(s):  
Lycopersicon Esculentum ◽  
Plant Growth ◽  
Significant Influence ◽  
Growth And Development ◽  
Red Light ◽  
Light Emitting ◽  
Red Led ◽  
In Vitro Plant ◽  
Normal Light

The aim of these studies was mainly to investigate the effects of monochromatic LEDs applied singly on the in vitro plant growth and morphogenesis. Various morphological and physiological parameters are considered that influence the growth and development of plants in vitro under red LED light as compared to those under normal light. Upon exposure to LED, in vitro-raised plants have shown significant improvements in growth and morphogenesis. In particular, red and blue lights, either alone or in combination, have a significant influence on plant growth. The present study gives an overview of the fundamentals of LEDs and describes their effects on in vitro plant growth and morphogenesis and their future potentials. The main objective of this study was to carry out line and combing ability of plant growth on tomato.

Synthesis, Crystal Structures, and Photoluminescence Properties of Ce3+-Doped Ca2LaZr2Ga3O12: New Garnet Green-Emitting Phosphors for White LEDs

2015 ◽  
Vol 119 (10) ◽  
pp. 5562-5569 ◽  
Author(s):  
Jiyou Zhong ◽  
Weidong Zhuang ◽  
Xianran Xing ◽  
Ronghui Liu ◽  
Yanfeng Li ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Photoluminescence Properties ◽  
White Leds

Luminescence Properties and Synthesis of SrMgAl10O17:Mn4+ Red Phosphor for White Light-Emitting Diodes

2016 ◽  
Vol 16 (4) ◽  
pp. 3489-3493 ◽  
Author(s):  
Renping Cao ◽  
Hongdong Xue ◽  
Xiaoguang Yu ◽  
Fen Xiao ◽  
Donglan Wu ◽  
...  
Keyword(s):  
Red Light ◽  
Solid State Reaction Method ◽  
Luminescence Properties ◽  
Conventional Solid State Reaction ◽  
Light Emitting ◽  
White Leds ◽  
Structure Morphology ◽  
Optimal Doping Concentration ◽  
Cie Chromaticity ◽  
White Light Emitting Diodes

A series of Mn4+ doped SrMgAl10O17 phosphors are synthesized by a conventional solid-state reaction method in air, and their crystal structure, morphology, and fluorescence properties are investigated. The luminescence properties show clearly that SrMgAl10O17:Mn4+ phosphor can be excited by UV (200–380 nm), near UV (380–420 nm), and blue (420–480 nm) bands of LEDs chip, and emits red light in the range of 600 nm to 750 nm with satisfying CIE chromaticity coordinates (0.7207, 0.2793). The optimal doping concentration of Mn4+ ion is ∼1 mol%, and its lifetime is ∼1.15 ms. The possible luminous mechanism of Mn4+ ion is discussed by Tanabe-Sugano diagram. These experiment results indicate that Mn4+ doped SrMgAl10O17 phosphors can be a potential application as a red-emitting phosphor candidate in white LEDs.

Synthesis and luminescence properties of (Lu0.95−xCe0.05)2Ca1+2xMg2Si3O12 silicate garnet phosphors and its applications

2016 ◽  
Vol 09 (03) ◽  
pp. 1650049
Author(s):  
Wei Xia ◽  
Xiyan Zhang ◽  
Liping Lu
Keyword(s):  
Light Emitting Diode ◽  
Red Light ◽  
Emission Spectra ◽  
Peak Wavelength ◽  
Excitation Peak ◽  
Light Emitting ◽  
White Leds ◽  
Reducing Atmosphere ◽  
Color Rendering ◽  
Silicate Garnet

Silicate garnet phosphors (Lu[Formula: see text]Ce[Formula: see text]Ca[Formula: see text]Mg2Si3O[Formula: see text] with [Formula: see text], 0.05, 0.1, and 0.15 were prepared by high-temperature solid-state reaction in a reducing atmosphere. The crystal structure, photoluminescence and luminescence of the phosphors were investigated. The optimum excitation peak wavelength of the phosphors ranged from 450[Formula: see text]nm to 490[Formula: see text]nm, matching the emission spectra of a blue light-emitting diode chip. The phosphors emit orange-red light after excitation that can be tuned from 589[Formula: see text]nm to 597[Formula: see text]nm by changing the concentration of calcium ions. In addition, their emission made them suitable for use in warm-white LEDs with a high-color rendering index.

A novel inequivalent double-site substituted red phosphor Li4AlSbO6:Mn4+ with high color purity: Structure, photoluminescence properties, and application in warm white LEDs

2021 ◽  
Author(s):  
Zhiyuan Li ◽  
Xuhui Zhang ◽  
Ji Wu ◽  
Rui Guo ◽  
Lan Luo ◽  
...  
Keyword(s):  
Rare Earth ◽  
Spectral Properties ◽  
Light Emitting Diode ◽  
Color Purity ◽  
Photoluminescence Properties ◽  
Red Phosphor ◽  
Light Emitting ◽  
White Leds ◽  
Red Phosphors ◽  
High Color Purity

Non-rare-earth Mn4+-doped oxide red phosphors received increasing attention in the white light-emitting diode (LED) field for their admirable chemical stability and spectral properties. Here, a new inequivalent double-site substituted Mn4+-doped...

The Structure and Photoluminescence Properties of Ca3Si2O7: Eu2+ Phosphor

2012 ◽  
Vol 509 ◽  
pp. 192-196
Author(s):  
Xing Hua Zhang ◽  
Zun Ming Lu ◽  
Fan Bin Meng ◽  
Long Hu ◽  
Xue Wen Xu ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Solid State Reaction Method ◽  
Emission Region ◽  
Photoluminescence Properties ◽  
Phosphor Particle ◽  
Sem Images ◽  
Host Matrix ◽  
Light Emitting ◽  
White Leds ◽  
Near Ultraviolet

A series of yellow-emitting phosphors based on a silicate host matrix, Ca3-xSi2O7: xEu2+, were prepared by solid-state reaction method. The structure and photoluminescent properties of the phosphors were investigated. The XRD results show that the Eu2+ substitution of Ca2+ does not change the structure of Ca3Si2O7 host. The SEM images display that phosphors aggregate obviously and the shape of the phosphor particle is irregular. The EDX results reveal that the phosphors consist of Ca, Si, O, and Eu elements. The Ca3-xSi2O7: xEu2+ phosphors can be excited at wavelength of 300-490 nm, which is suitable for the emission band of near ultraviolet or blue light-emitting-diode (LED) chips. The phosphors exhibit a broad emission region from 520 to 650 nm and the emission peak centered at 568 nm. The phosphor for has the strongest excitation and emission intensity, and the energy transfer style between Eu2+ ions is quadrupole-quadrupole interaction for higher concentration Eu2+ doped Ca3Si2O7 phosphor. The Ca3-xSi2O7: xEu2+ phosphors can be used as candidates for white LEDs.

scholarly journals Growth, Nutritional Quality, and Energy Use Efficiency of Hydroponic Lettuce as Influenced by Daily Light Integrals Exposed to White versus White Plus Red Light-emitting Diodes

HortScience ◽  
2019 ◽  
Vol 54 (10) ◽  
pp. 1737-1744 ◽  
Author(s):  
Zhengnan Yan ◽  
Dongxian He ◽  
Genhua Niu ◽  
Qing Zhou ◽  
Yinghua Qu
Keyword(s):  
Nutritional Quality ◽  
Energy Use ◽  
Light Emitting Diodes ◽  
Red Light ◽  
Dry Weight ◽  
Light Emitting ◽  
Energy Use Efficiency ◽  
White Leds ◽  
Use Efficiency ◽  
Red Leds

Few researchers examined different red light amounts added in white light-emitting diodes (LEDs) with varied daily light integrals (DLIs) for hydroponic lettuce (Lactuca sativa L.). In this study, effects of DLI and LED light quality (LQ) on growth, nutritional quality, and energy use efficiency of hydroponic lettuce were investigated in a plant factory with artificial lighting (PFAL). Hydroponic lettuce plants (cv. Ziwei) were grown for 20 days under 20 combinations of five levels of DLIs at 5.04, 7.56, 10.08, 12.60, and 15.12 mol·m−2·d−1 and four LQs: two kinds of white LEDs with red to blue ratio (R:B ratio) of 0.9 and 1.8, and two white LEDs plus red chips with R:B ratio of 2.7 and 3.6, respectively. Results showed that leaf and root weights and power consumption based on fresh and dry weights increased linearly with increasing DLI, and light and electrical energy use efficiency (LUE and EUE) decreased linearly as DLI increased. However, no statistically significant differences were found in leaf fresh and dry weights and nitrate and vitamin C contents between DLI at 12.60 and 15.12 mol·m−2·d−1. Also, no effects of LQ on leaf dry weight of hydroponic lettuce were observed at a DLI of 5.04 mol·m−2·d−1. White plus red LEDs with an R:B ratio of 2.7 resulted in higher leaf fresh weight than the two white LEDs. LUE increased by more than 20% when red light fraction increased from 24.2% to 48.6%. In summary, white plus red LEDs with an R:B ratio of 2.7 at DLI at 12.60 mol·m−2·d−1 were recommended for commercial hydroponic lettuce (cv. Ziwei) production in PFALs.

scholarly journals Effect of Light Emitting Diode (LED) Spectra on Plant Growth

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Nur Syahirah Talib ◽  
Diyana Jamaludin ◽  
Nur Sakinah Abdul Malek
Keyword(s):  
Chlorophyll Content ◽  
Growth And Development ◽  
Control Treatment ◽  
White Led ◽  
Hydroponic System ◽  
Light Emitting ◽  
White Leds ◽  
Red Led ◽  
Lettuce Growth ◽  
Number Of Leaves

The effect of lights generated by red, blue and white light emitting diodes (LED) on growth and development of lettuce were investigated and compared with lettuce without supplemental lighting. A vertical multi-tier hydroponic system was used to grow lettuce. Each tier consisted of 60 heads of lettuce with different LED colour and one tier without LED was used as control. The following measurements on plant physiology were taken: number, length and chlorophyll content of leaves, height and weight of plants. Based on number of leaves, red LED shows the highest number of leaves compared to lettuce under blue, white and control treatment. The similar trend also can be found in the lengths of leaves which shows the highest length produce under red LED.  Red LED also produce highest weight of lettuce by 28% as compared to white LED. White LED improved lettuce growth development in the height by 13% and amount of chlorophyll content. Lettuce grown under blue LED shows lowest growth and development compared to lettuce grown under red and white LEDs based on parameters above, and lettuce without LED were died within 2 weeks.  This result indicated that the red LED was the most effective spectra in growth response of lettuce plants. This study also demonstrates the effectiveness of LED in improving lettuce growth on vertical multi-tier hydroponic system.

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