scholarly journals LUMINESCENCE BEHAVIOUR OF DY3+ ION DOPED MAGNESIUM SULFOBORATE PHOSPHOR FOR WHITE LIGHT EMITTING DIODES

2020 ◽  
Vol 1 (1) ◽  
pp. 11-15
Author(s):  
A. S. Dalhatu ◽  
R. Hussin ◽  
B. Ibrahim ◽  
Y. A. Yamusa ◽  
A. Baballe
Keyword(s):  
Solid State Reaction Method ◽  
Lanthanide Ions ◽  
Luminescence Properties ◽  
State University ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
White Leds ◽  
Trivalent Lanthanide ◽  
Yellow Region ◽  
White Light Emitting Diodes

Several studies showed the interesting properties of trivalent lanthanide ions when doped in various types of phosphor. Magnesium sulfoborate phosphor doped with different concentrations of Dy3+ were synthesized using solid-state reaction method at 850 °C for 4 hours. The samples were characterized by X-ray Diffraction (XRD). The excitation and luminescence properties of MgO-SO4-B2O3:Dy3+ were determined. The emission spectrum of Dy3+ ion doped MgO-SO4-B2O3 phosphor exhibit three bands at 480 nm, 573 nm and 660 nm with excitation of 386 nm due to 4F9/2 →6H15/2, 6H13/2 and 6H11/2 of Dy3+ transitions, respectively. The excitation spectrum of Dy3+ ion doped MgO-SO4-B2O3 phosphor display several bands at 347 nm, 362 nm, 386 nm, 426 nm, 449 nm and 469 nm with emission of 573 nm, which is in agreement with the ultraviolet LED (349.9–410 nm) and blue LED (450–470 nm). An intense in the emission peak at 573 nm in the yellow region was observed with the 0.5 Dy2O3. The luminescence properties of phosphor show that MgO-SO4-B2O3:Dy3+ phosphor could be potentially used as white LEDs. Dalhatu, A. S. | Department of Physics, Bauchi State University Nigeria, 65 Gadau, Bauchi, Nigeria

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.

scholarly journals A promising Sr5 (PO4)3Br:RE3+ (RE3+= Dy3+, Eu3+, and Tb3+) Phosphors for Near UV Excited White LED and Display Devices

2020 ◽  
Vol 9 (4) ◽  
pp. 2062-2067
Keyword(s):  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
White Leds ◽  
Display Devices ◽  
Characteristic Emission ◽  
Ft Ir ◽  
White Light Emitting Diodes ◽  
Uv Excitation ◽  
Ft Ir Spectroscopy

Single phase Sr5 (PO4 )3Br:RE3+ (RE3+= Dy3+, Eu3+ or Tb3+) phosphors were prepared by solid state reaction method and optical properties were investigated for the possible applications in white light emitting diodes (LED) and display devices. Prepared phosphors are characterized by X-ray diffraction, scanning electron microscopy, photoluminescence (PL) and FT-IR spectroscopy. The PL properties of Sr5 (PO4 )3Br:Dy3+ phosphor shows the characteristic emission of blue (479 nm) and yellow (575 nm) light under near UV excitation of 387nm, Sr5 (PO4 )3Br:Eu3+ shows characteristic orange (590 nm) and red (613 nm) under near UV excitation of 396 nm and Sr5 (PO4 )3Br:Tb3+ shows green (545 nm) emission under 379 nm excitation. The results indicate that the RE3+ activated bromoapatite phosphor could be promising candidate for near UV-based white LEDs and display devices.

Synthesis of Sr2Si5N8:Eu2+ Phosphor for Enhanced Red Emission

2011 ◽  
Vol 233-235 ◽  
pp. 2705-2709 ◽  
Author(s):  
Van Duong Luong ◽  
Wen Tao Zhang ◽  
Hong Ro Lee
Keyword(s):  
Single Phase ◽  
Luminescence Properties ◽  
Heating Process ◽  
X Ray Diffraction ◽  
Red Phosphor ◽  
Red Emission ◽  
Light Emitting ◽  
White Leds ◽  
Xrd Patterns ◽  
White Light Emitting Diodes

For removing impurities to improve luminescence properties, Eu2+- activated Sr2Si5N8 red phosphor for white light-emitting diodes (LEDs) was prepared by multiple heat-treatment synthesis which includes carbothermal reduction and nitridation. The X-ray diffraction (XRD) patterns were showed the standard single phase of Sr2Si5N8. With an optimized amount of Eu2+ (2 at. %) dopant, the broad excitation band of Sr2Si5N8:Eu2+ indicated that the phosphor was suitable for application of white LEDs with UV or blue chip, and red emission peak at 628 nm in spectra originating from the 4f65d1→4f7 transition of Eu2+ ion. After third heating process, luminescence properties of the obtained phosphor were improved obviously and higher than commercial YAG:Ce3+ phosphor.

A new langbeinite-type phosphate K2GdHf(PO4)3: synthesis, crystal structure, band structure and luminescence properties

2020 ◽  
Vol 76 (8) ◽  
pp. 771-778
Author(s):  
Hua Nan ◽  
Li Chen ◽  
Rui-Juan Zhang ◽  
Dan Zhao
Keyword(s):  
Optical Transition ◽  
Blue Emission ◽  
Large Family ◽  
Luminescence Properties ◽  
X Ray Diffraction ◽  
Blue Emission Band ◽  
Light Emitting ◽  
Direct Band ◽  
Cie Chromaticity ◽  
White Light Emitting Diodes

Langbeinite-type compounds are a large family that include phosphates, sulfates and arsenates, and which are accompanied by interesting physical properties. This work reports a new disordered langbeinite-type compound, K2GdHf(PO4)3 [dipotassium gadolinium hafnium tris(phosphate)], and its structure as determined by single-crystal X-ray diffraction. Theoretical studies reveal that K2GdHf(PO4)3 is an insulator with a direct band gap of 4.600 eV and that the optical transition originates from the O-2p→Hf-5d transition. A Ce3+-doped phosphor, K2Gd0.99Ce0.01Hf(PO4)3, was prepared and its luminescence properties studied. With 324 nm light excitation, a blue emission band was observed due to the 5d 1→4f 1 transition of Ce3+. The average luminescence lifetime was calculated to be 5.437 µs and the CIE chromaticity coordinates were (0.162, 0.035). One may expect that K2Gd0.99Ce0.01Hf(PO4)3 can be used as a good blue phosphor for three-colour white-light-emitting diodes (WLEDs).

Synthesis, structure and luminescence properties of new blue-green-emitting garnet-type Ca3Zr2SiGa2O12:Ce3+ phosphor for near-UV pumped white-LEDs

RSC Advances ◽  
2016 ◽  
Vol 6 (3) ◽  
pp. 2155-2161 ◽  
Author(s):  
Jiyou Zhong ◽  
Weidong Zhuang ◽  
Xianran Xing ◽  
Ronghui Liu ◽  
Yanfeng Li ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Luminescence Properties ◽  
Light Emitting ◽  
White Leds ◽  
White Light Emitting Diodes

A new blue-green-emitting garnet-type phosphor Ca3Zr2SiGa2O12:Ce3+ has been explored for n-UV pumped white light-emitting diodes.

scholarly journals Luminescence properties of Eu3+ activated Y2MoO6 powders calcined at different temperatures

2020 ◽  
Vol 14 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Nadezda Stankovic ◽  
Marko Nikolic ◽  
Branislav Jelenkovic ◽  
Nina Daneu ◽  
Jelena Maletaskic ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
White Leds ◽  
Calcination Temperatures ◽  
Transmission Electron ◽  
Light Region ◽  
Lower Treatment ◽  
Different Temperatures ◽  
White Light Emitting Diodes

In the last decade, an immense progress has been made in white LEDs, mainly due to the development of red-emitting phosphors. In this paper, we report on the synthesis of Eu3+ activated Y2MoO6 by a self-initiated and self-sustained method. The obtained powder was calcined at various temperatures in the 600-1400?C range and examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence spectroscopy (PL). The results revealed that all powders are single phase Y2MoO6:Eu3+, with particle size in the nanorange at lower treatment temperatures (600 and 800?C) and in the microrange at higher calcination temperatures (1000-1400?C). The obtained powders are promising materials for white light-emitting diodes as they can efficiently absorb energy in 324-425 nm region (near-UV to blue light region) and emit at 611 nm in the red region of the spectrum, while exhibiting high thermal and chemical stability.

Luminescence Properties of a Novel Blue-Emitting Phosphor NaBaBO3:Tm3+,K+

2015 ◽  
Vol 833 ◽  
pp. 39-43 ◽  
Author(s):  
Jiang Hui Zheng ◽  
Qi Jin Cheng ◽  
Li Li Ying ◽  
Li Han Cai ◽  
Chao Chen
Keyword(s):  
Dipole Interaction ◽  
Solid State Reaction Method ◽  
Concentration Quenching ◽  
Luminescence Properties ◽  
Photoluminescence Intensity ◽  
Quenching Mechanism ◽  
Light Emitting ◽  
Near Ultraviolet ◽  
Chromaticity Coordinate ◽  
White Light Emitting Diodes

A novel blue-emitting phosphor NaBaBO3doped with Tm3+was prepared using a conventional high temperature solid-state reaction method. Its crystal structure and luminescence properties were studied. Photoluminescence measurements indicate that the phosphor features a satisfactory blue performance due to the1D2→3F4transition of Tm3+with the highest photoluminescence intensity located at 460 nm excited by 359 nm near-ultraviolet (NUV) light. In addition, the concentration of Tm3+was adjusted in order to obtain the optimum emission intensity. When the Tm3+concentration in NaBaBO3is 6.0 mol% the maximum intensity can be obtained. The concentration quenching occurs when Tm3+concentration is beyond 6.0 mol% and the concentration quenching mechanism can be explained by the dipole–dipole interaction. The measured chromaticity coordinate for the NaBaBO3:Tm3+phosphor under 359 nm excitation is determined to be (0.1470, 0.1090). The present work suggests that the NaBaBO3:Tm3+,K+phosphor is a promising blue-emitting material for NUV white light-emitting diodes.

Cerium Doped Garnet Phosphors for Application in White GaN-based LEDs

2001 ◽  
Vol 667 ◽  
Author(s):  
Jennifer L. Wu ◽  
Steven P. Denbaars ◽  
Vojislav Srdanov ◽  
Henry Weinberg
Keyword(s):  
White Light ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
White Leds ◽  
Garnet Phase ◽  
Gan Led ◽  
Traditionally Prepared ◽  
White Light Emitting Diodes ◽  
Down Conversion ◽  
Subsequent Emission

ABSTRACTRecently, renewed interest has emerged for the development of visible light, down-converting phosphors for application in white light emitting diodes (LEDs). In such devices, a blue GaN LED can act as a primary light source, serving as an efficient pump to excite photoluminescence in a phosphor with subsequent emission occurring at lower energies. The combination of blue light from the LED chip and emission from the phosphor(s) produces white light. It was recently reported that a combinatorial approach to synthesize and screen potential inorganic phosphors for use in white LEDs could aid in identifying improved phosphors for blue to yellow down conversion. Solid state thin-film arrays (libraries) based on the garnet structure (A1−x,Bx)3−z(C1−y,Dy)5O12:Ce3+z, where A, B = Y, Gd, Lu, La; C., D = Al, Ga; x and y = 0 to 1.0; and z = 0.03, were synthesized, and x-ray diffraction was used to select library samples of the crystalline garnet phase. Libraries of these various garnets were then characterized spectroscopically and their properties compared to traditionally prepared bulk powder phosphors of similar composition. Emission and excitation trends show that as larger cations are substituted for Y (A = Y), emission and excitation are red-shifted and as larger cations are substituted for Al (C = Al), emission and excitation are blue-shifted. If smaller cations are substituted for Y and Al an opposite trend is observed. Temperature dependence photoluminescence measurements and emission/excitation trends are also examined.

Broadband near-infrared BaMSi3O9:Cr3+ (M = Zr, Sn, Hf) phosphors for light-emitting diode applications

2021 ◽  
Author(s):  
Yan Zhang ◽  
Yanjie Liang ◽  
Shihai Miao ◽  
Dongxun Chen ◽  
Shao Yan ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Near Infrared ◽  
Light Emitting Diode ◽  
Solid State Reaction Method ◽  
Luminescence Properties ◽  
Light Emitting ◽  
Reaction Method ◽  
Simple Solid State Reaction

A series of Cr3+-doped BaMSi3O9 (M = Zr, Sn, Hf) near-infrared emitting phosphors with tunable luminescence properties have been successfully synthesized by using a simple solid-state reaction method. The developed...

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