Synthesis and luminescence properties of the red phosphor CaZrO3:Eu3+ for white light-emitting diode application

Open Physics ◽  
2011 ◽  
Vol 9 (4) ◽  
Author(s):  
Junli Huang ◽  
Liya Zhou ◽  
Yuwei Lan ◽  
Fuzhong Gong ◽  
Qunliang Li ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diode ◽  
Red Light ◽  
Average Diameter ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
Light Emitting ◽  
Near Ultraviolet ◽  
Light Region

AbstractEu3+-doped CaZrO3 phosphor with perovskite-type structure was synthesized by the high temperature solid-state method. The samples were characterized by X-ray diffraction, scanning electron microscopy, fluorescence spectrophotometer and UV-vis spectrophotometer, respectively. XRD analysis showed that the formation of CaZrO3 was at the calcinations temperature of 1400°C. The average diameter of CaZrO3 with 4 mol% doped-Eu3+ was 2µm. The PL spectra demonstrated that CaZrO3:Eu3+ phosphor could be excited effectively in the near ultraviolet light region (397 nm) and emitted strong red-emission lines at 616 nm corresponding to the forced electric dipole 5 D 0 → 7 F 2 transitions of Eu3+. Meanwhile, the light-emitting diode was fabricated with the Ca0.96ZrO3:Eu0.043+ phosphor, which can efficiently absorb ∼ 400 nm irradiation and emit red light. Therefore Ca0.96ZrO3:Eu0.043+ may have applications for a near ultraviolet InGaN chip-based white light-emitting diode.

Photoluminescence Properties of CaBi4Ti4O15:Dy3+ for White Light-Emitting Diodes

2014 ◽  
Vol 1053 ◽  
pp. 8-14 ◽  
Author(s):  
Xin Wang ◽  
Rui Rui Cui ◽  
Chao Yong Deng
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Yellow Emission ◽  
Potential Candidate ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
Light Emitting ◽  
Near Ultraviolet ◽  
Fluorescence Measurements ◽  
White Light Emitting Diodes

This paper studied the structural and optical properties of Dy3+-doped CaBi4Ti4O15 phosphors synthesized by a traditional solid state method. The phosphors have been characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and fluorescence measurements. Upon 450 nm blue light excitation, the phosphors show yellow emission centered at 574 nm with the color coordination of (x=0.44, y=0.54). And the phosphors exhibit a tunable white color emission under the near ultraviolet source by adjusting the ratio of Dy3+ appropriately. The optimal composition of Ca0.93Bi4Ti4O15:0.07Dy3+ generates white light with the color chromaticity of (x=0.31, y=0.36), indicating that CaBi4Ti4O15:Dy3+ phosphor would be a potential candidate for white light emitting diodes (LEDs) applications.

Effects of electron-withdrawing groups in imidazole-phenanthroline ligands and their influence on the photophysical properties of EuIII complexes for white light-emitting diodes

2017 ◽  
Vol 41 (18) ◽  
pp. 9826-9839 ◽  
Author(s):  
Boddula Rajamouli ◽  
Rachna Devi ◽  
Abhijeet Mohanty ◽  
Venkata Krishnan ◽  
Sivakumar Vaidyanathan
Keyword(s):  
Thin Film ◽  
Quantum Yield ◽  
White Light ◽  
Light Emitting Diode ◽  
Photophysical Properties ◽  
Red Light ◽  
Europium Complexes ◽  
Light Emitting ◽  
White Light Emitting Diodes ◽  
Phenanthroline Ligands

The red light emitting diode (LED) was fabricated by using europium complexes with InGaN LED (395 nm) and shown digital images, corresponding CIE color coordinates (red region) as well as obtained highest quantum yield of the thin film (78.7%).

Photoluminescence studies on LiNa5(PO4)2:Dy3+, Sm3+ phosphor

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Miyapuram Ravi ◽  
Ghanta Pushpa Chakrapani ◽  
Mandava Balachandrika ◽  
Pavuluri Vasudevarao ◽  
Chendela Nageswararao ◽  
...  
Keyword(s):  
White Light ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
New Class ◽  
Light Region ◽  
Crystalline Nature ◽  
Photoluminescence Studies ◽  
White Light Emitting Diodes ◽  
Good Agreement ◽  
Pure White

Abstract This paper describes the preparation, structure and photoluminescence properties of a new class LiNa5(PO4)2:Dy3+, Sm3+-phosphor. Crystalline nature confirmed by X-ray diffraction. The phases obtained are in good agreement with the standard phase. Excitation dependence and concentration effect on luminescence features are investigated. Color purity and optical bandgap are also estimated for the LiNa5(PO4)2:Dy3+, Sm3+ phosphors. The result shows LiNa5(PO4)2:Dy3+, Sm3+-phosphor excited by 374 nm nUV light produces pure white light than others. Admixing of 4f configurations and energy transfer between dopants are identified while varying the concentration of Sm3+. The CIE coordinates for LiNa5(PO4)2:0.05Dy3+, 0.05Sm3+ (x = 0.309, y = 0.332) are positioned well in white light region and very close to pure white light. The present study on LiNa5(PO4)2:Dy3+, Sm3+-phosphor suggests that it is useful for the fabrication of white light emitting diodes.

scholarly journals Far-Red Light Acclimation for Improved Mass Cultivation of Cyanobacteria

Metabolites ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 170 ◽  
Author(s):  
Alla Silkina ◽  
Bethan Kultschar ◽  
Carole A. Llewellyn
Keyword(s):  
Biomass Production ◽  
White Light ◽  
Light Emitting Diode ◽  
Red Light ◽  
Industrial Biotechnology ◽  
Light Conditions ◽  
Light Emitting ◽  
Mass Cultivation ◽  
Chlorogloeopsis Fritschii ◽  
Bioactive Product

Improving mass cultivation of cyanobacteria is a goal for industrial biotechnology. In this study, the mass cultivation of the thermophilic cyanobacterium Chlorogloeopsis fritschii was assessed for biomass production under light-emitting diode white light (LEDWL), far-red light (FRL), and combined white light and far-red light (WLFRL) adaptation. The induction of chl f was confirmed at 24 h after the transfer of culture from LEDWL to FRL. Using combined light (WLFRL), chl f, a, and d, maintained the same level of concentration in comparison to FRL conditions. However, phycocyanin and xanthophylls (echinone, caloxanthin, myxoxanthin, nostoxanthin) concentration increased 2.7–4.7 times compared to LEDWL conditions. The productivity of culture was double under WLFRL compared with LEDWL conditions. No significant changes in lipid, protein, and carbohydrate concentrations were found in the two different light conditions. The results are important for informing on optimum biomass cultivation of this species for biomass production and bioactive product development.

Near-ultraviolet chip-based phosphor-converted solar-spectrum white light-emitting diode

2020 ◽  
Vol 59 (01) ◽  
pp. 1
Author(s):  
Xinran Zhang ◽  
Shuo Zhang ◽  
Guodong Wang ◽  
Yunyu Wang ◽  
Meng Liang ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diode ◽  
Solar Spectrum ◽  
Light Emitting ◽  
Near Ultraviolet

scholarly journals Synthesis and Photoluminescence Properties of Eu3+-Doped Na2YMg2V3O12: A Novel Red-Emitting Phosphor for White-Light-Emitting Diodes

2021 ◽  
Author(s):  
Weiyi Zhang ◽  
Yanqiu Shao ◽  
Ying Zhu ◽  
Yingying Shao ◽  
Zhaohui Huang ◽  
...  
Keyword(s):  
Solid State ◽  
White Light ◽  
Emission Band ◽  
Red Light ◽  
Solid State Reactions ◽  
Broad Emission Band ◽  
Light Emitting ◽  
Near Ultraviolet ◽  
Broad Emission ◽  
Red Emitting Phosphor

Abstract The fabrication and luminescent properties of novel Na2YMg2V3O12:Eu3+ phosphors produced by conventional solid-state reactions were investigated. Self-activated emission of the Na2YMg2V3O12 host produces a broad emission band ranging from 400 to 700 nm with a maximum peak at 530 nm, ascribed to the charge transfer in the (VO4)3− groups. Excitation with near-UV (365 nm) light causes the Na2YMg2V3O12:Eu3+ phosphors to emit bright red light, including both the broad emission band of the (VO4)3− groups and the sharp emission peaks of Eu3+ ions. At a quenching concentration of 0.03 mol, the Eu3+ ion emission peaks were located at 597, 613, 654 and 710 nm. As-prepared Na2YMg2V3O12:Eu3+ phosphors also exhibited stable emission at high temperatures. Furthermore, a designed and packaged white-light-emitting diode (WLED) lamp, including the obtained phosphors, commercial (Ba,Sr)2SiO4:Eu2+ green phosphors, BaMgAl10O17:Eu2+ blue phosphors and a near-ultraviolet (n-UV) chip, emitted bright white light with a good chromaticity coordinate of (0.3068, 0.3491), a satisfactory colour rendering index of 88.20 and a properly correlated colour temperature of 4460.52 K. These results indicate the potential of this Na2YMg2V3O12:Eu3+ phosphor as a red-emitting phosphor for solid-state illumination.

The Effect of Needle Diameter on Optical Properties and Morphological Structure of La2O3- PVA Phosphor Nanofibers Prepared by Electrospinning Method

2020 ◽  
Vol 301 ◽  
pp. 18-26
Author(s):  
Hasma A. Wahab ◽  
Zainuriah Hassan ◽  
Naser Mahmoud Ahmed
Keyword(s):  
Optical Properties ◽  
Energy Gap ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Morphological Structure ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
Electrospinning Method ◽  
Needle Diameter

Lanthanum Oxide-Polyvinyl alcohol (La2O3-PVA) phosphor nanofibers were prepared by electrospinning and investigation of the effect of needle diameter on the optical properties and morphological structure at the nanofibers was carried out. The average diameter of phosphor nanofibers have been evaluated for five different needle diameters. The resulting phosphor nanofibers were observed and anaylzed by X-ray diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), Ultraviolet-visible Spectroscopy (UV-Vis) and HPC-2 Lightsource Colorimeter. The La2O3-PVA phosphor nanofibers were used in light down-conversion of UV light (365 nm) for the white light-emitting diode (WLED) application. The chromaticity coordinates (CIE) and correlated colour temperature (CCT) were measured for different phosphor nanofibers with different sizes of needle diameter (0.45,0.55,0.65,0.75,1.1) mm. The results revealed that the phosphor nanofibers formed by needle diameter of 0.65 mm places macromolecule in a better order and the average diameter increase from 40.08 nm to 87.27 nm after annealing followed by increasing in atomic percentage of lanthanum. The energy gap of resulting phosphor nanofibers is 3.5365 eV. An optimum colour rendering index (CRI) value of 70.20 is obtained. The white phosphor exhibited CIE values of 0.3536, 0.407 and CCT of 4890 K.

High CRI in phosphor-in-doped glass under near-ultraviolet excitation for warm white light-emitting diode

2021 ◽  
Vol 229 ◽  
pp. 117684
Author(s):  
A. Arellano-Morales ◽  
J. Molina-González ◽  
H. Desirena ◽  
J.M. Bujdud-Perez ◽  
S. Calixto
Keyword(s):  
White Light ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Ultraviolet Excitation ◽  
Near Ultraviolet ◽  
Warm White Light ◽  
Doped Glass

A SILVER-COATED SINUSOIDAL SUB-WAVELENGTH STRUCTURE WITH POLARIZATION FEATURE FOR LIGHT EMITTING DIODE

2009 ◽  
Vol 16 (04) ◽  
pp. 631-634 ◽  
Author(s):  
CHENG-HAO KO ◽  
JIAN-SHIAN LIN ◽  
CHANG-TAI CHEN ◽  
NIEN-PO CHEN
Keyword(s):  
Light Emitting Diode ◽  
Red Light ◽  
Fdtd Method ◽  
Dielectric Materials ◽  
Transmission Efficiency ◽  
Light Emitting ◽  
Light Region ◽  
Fluorescence Efficiency ◽  
Difference Time ◽  
Sub Wavelength

A two-dimensional sub-wavelength grating (SWG) is fabricated on light-emitting diodes (LEDs). The SWG is simulated by finite-difference time-domain (FDTD) method. The SWG surface has silver-coated dielectric materials with sinusoidal structures, 175 nm period and 125 m depth of groove. When the incident wave is in the red light region of 600–700nm, the transmission efficiency of TM propagated light will reach 0.82. If this SWG structure is applied in LCD direct backlight module, the lower polarization piece can be replaced and fluorescence efficiency of LED can be improved.

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