scholarly journals Luminescence properties of Mn4+-doped CaAl2O4as a red emitting phosphor for white LEDs

2021 ◽  
Vol 63 (3) ◽  
pp. 3-7
Author(s):  
Thi Kim Chi Nguyen ◽  
◽  
Duy Hung Nguyen ◽  
Tan Vinh Le ◽  
Thanh Vu Tran ◽  
...  
Keyword(s):  
Great Promise ◽  
White Led ◽  
X Ray Diffraction ◽  
Red Phosphor ◽  
White Leds ◽  
Broadband Emission ◽  
Structure Morphology ◽  
Red Luminescence ◽  
Co Precipitation ◽  
Red Emitting Phosphor

A series of Mn4+-activated CaAl2O4 (CAO) compounds were synthesized by co-precipitation to seek a candidate for a red-emitting phosphor to be employed in a white LED. The crystal structure, morphology, and fluorescence properties of the as-obtained phosphors were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL). The deep red luminescence of Mn4+ in CaAl2O4 is reported and discussed. The excitation spectrum exhibited broadband emission between 260 and 550 nm with three peaks dominating at 320 nm due to the transition of 4A24T1. Theemission spectra between 600 to 720 nm displays an overwhelming emission peak at 654 nm owing to the 2E4A2 transition of Mn4+ ion.This research demonstrates the great promise of CaAl2O4:Mn4+ as a commercial red phosphor in warm white LEDs and opens up new avenues for the exploration of novel non-rare-earth red-emitting phosphors.

Synthesis and warm-white LED applications of an efficient narrow-band red emitting phosphor, Rb2ZrF6:Mn4+

2017 ◽  
Vol 5 (29) ◽  
pp. 7253-7261 ◽  
Author(s):  
L. Y. Wang ◽  
E. H. Song ◽  
Y. Y. Zhou ◽  
T. T. Deng ◽  
S. Ye ◽  
...  
Keyword(s):  
Narrow Band ◽  
Precipitation Method ◽  
White Led ◽  
Red Phosphor ◽  
Yellow Phosphor ◽  
Co Precipitation ◽  
Red Emitting Phosphor

Phosphor Rb2ZrF6:Mn4+has been synthesizedviaa co-precipitation method. Series of WLEDs were fabricated by combining YAG:Ce3+yellow phosphor and different amount of Rb2ZrF6:Mn4+red phosphor with InGaN blue chips.

Co-precipitation synthesis and photoluminescence properties of BaTiF6:Mn4+: an efficient red phosphor for warm white LEDs

2018 ◽  
Vol 6 (1) ◽  
pp. 127-133 ◽  
Author(s):  
Yong Liu ◽  
Guojun Gao ◽  
Lin Huang ◽  
Yiwen Zhu ◽  
Xuejie Zhang ◽  
...  
Keyword(s):  
Emission Line ◽  
Photoluminescence Properties ◽  
Broad Absorption ◽  
Red Phosphor ◽  
White Leds ◽  
Blue Region ◽  
Precipitation Synthesis ◽  
Co Precipitation ◽  
Sharp Emission Line

BaTiF6:Mn4+: a fluoride-based red phosphor with a sharp emission line and broad absorption in the blue region used for warm WLEDs.

A Promising Energy-Saving and Environmental-Friendly Lighting Device: High CRI White LED with Phosphor Materials

2016 ◽  
Vol 848 ◽  
pp. 446-453
Author(s):  
Sheng Liu ◽  
Bei Ying Zhou ◽  
Shi Jia Gu ◽  
Lian Jun Wang ◽  
Wan Jiang ◽  
...  
Keyword(s):  
Environmental Scanning Electron Microscopy ◽  
Luminescence Spectra ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Green Phosphor ◽  
Red Phosphor ◽  
White Leds ◽  
Phase Surface ◽  
Color Rendering ◽  
Fluorescence Spectrometer

Two kinds of commercial LED phosphors (green phosphor LuAG:Ce3+ and red phosphor CaAlSiN3:Eu2+) with polymethyl methacrylate (PMMA) powders were mixed to prepare film phosphors with tunable emission peak in photoluminescence spectrum by flat vulcanizing machine under the temperature of 170 oC and pressure of 2 MPa. The physical phase, surface morphology, transmittance, luminescence spectra of samples were characterized by means of X-ray diffraction (XRD), Environmental scanning electron microscopy (ESEM), Ultraviolet-Visible (UV-Vis) spectrophotometry and Fluorescence spectrometer. The results show that the film phosphors phase was consistent with raw phosphors, phosphor particles were uniformly distributed, and fluorescence spectra with different proportions of phosphors in different position can be adjusted. Tested by HSP 3000 spectrum analyzer, the white LEDs fabricated by blue chip and composite film phosphor containing 5 wt% green phosphor and 1.5 wt.% red phosphor, which refers to the remote excitation technique, possessed color coordinate of (0.3715, 0.3280) and color rendering index (CRI) of 87 when it was driven at power of 36 V/140 mA, reaching the international advanced level.

HIGH YIELD NANOPARTICLES SYNTHESIS OF EUROPIUM-DOPED YTTRIUM OXIDE RED-PHOSPHOR USING AN ORGANIC COMPOUND

NANO ◽  
2009 ◽  
Vol 04 (03) ◽  
pp. 141-145 ◽  
Author(s):  
WOO JUNG PARK ◽  
TAKAKI MASAKI ◽  
DAE HO YOON
Keyword(s):  
High Efficiency ◽  
Luminescent Properties ◽  
Synthesis Temperature ◽  
High Yield ◽  
X Ray Diffraction ◽  
Promising Alternative ◽  
Red Phosphor ◽  
Grain Sizes ◽  
Phase Precursor ◽  
Red Emitting Phosphor

This paper reports an approach for enhancing the luminescent properties of Y2O3:Eu3+ nanophosphors with cellulose, using a liquid phase precursor (LPP) process. The nanosized [Formula: see text] particles showed a powder X-ray diffraction pattern, corresponding to the reference, and were highly crystalline. The grain sizes of the samples synthesized at 600°C for 1 h were estimated to be approximately 19 nm. The particle sizes of the samples increased with increasing synthesis temperature and the morphology was cleaned and without impurities. In addition, all the samples had a smaller particle size than that of the commercial product. The PL spectrum consisted of weak bands at 581, 587, 593, and 599 nm, corresponding to the 5 D 0 → 7 F 1 transition, and sharp peaks with a maximum intensity occurring at approximately 610 nm, due to the 5 D 0 → 7 F 2 transition of Eu 3+. These results suggest that Y 2 O 3: Eu 3+ is a promising alternative red-emitting phosphor for high efficiency resolution display applications.

The Luminescence Properties of Green YPO4: Tb3+,Ce3+ Phosphors for WLED

2014 ◽  
Vol 989-994 ◽  
pp. 391-394
Author(s):  
Jian Li ◽  
Li Min Dong ◽  
Qin Li ◽  
Zhi Dong Han
Keyword(s):  
High Performance ◽  
Light Emitting Diode ◽  
Bath Temperature ◽  
Fourth Generation ◽  
Luminescent Material ◽  
X Ray Diffraction ◽  
Green Phosphor ◽  
Light Emitting ◽  
Structure Morphology ◽  
Co Precipitation

LED as the fourth generation light source has been extensively studied. In order to get a high-performance White Light Emitting Diode (WLED) green phosphor, YPO4:Ce3+,Tb3+ was prepared by co-precipitation. It was excited at 380nm. The structure, morphology, fluorescence property and colorimetry of the phosphors were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectrophotometer. Final results show the optimal concentration ratio are 1:0.05:0.01. The crystal grain of luminescent material is 200 nm. When the bath temperature is 80°C and calcined at 1000°C for 3h, the luminescence performance of the luminescent material is excellent.

scholarly journals Synthesis and photoluminescence of Mn4+ activated ternary-alkaline fluoride K2NaGaF6 red phosphor for warm-white LED application

RSC Advances ◽  
2017 ◽  
Vol 7 (79) ◽  
pp. 50396-50402 ◽  
Author(s):  
Shijie Qiu ◽  
Hengwei Wei ◽  
Mengmeng Wang ◽  
Shuai Zhang ◽  
Yang Zhou ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Band Structure ◽  
Electronic Band Structure ◽  
Luminescence Properties ◽  
White Led ◽  
Electronic Band ◽  
Red Phosphor ◽  
Structure Morphology

A novel ternary-alkaline red emitting fluoride phosphor K2NaGaF6:Mn4+ was successfully synthesized. The crystal structure, morphology, electronic band structure and luminescence properties of K2NaGaF6:Mn4+ phosphors were investigated in detail.

A strong zero-phonon line red phosphor BaNbF7:Mn4+ for white LEDs

2020 ◽  
Vol 7 (18) ◽  
pp. 3371-3378
Author(s):  
Yang Zhou ◽  
Xiaoming Wang ◽  
Cuiping Wang ◽  
Tian Zhang ◽  
Yonggang Wang ◽  
...  
Keyword(s):  
Blue Light ◽  
Emission Intensity ◽  
Precipitation Method ◽  
Zero Phonon Line ◽  
Red Phosphor ◽  
Phonon Line ◽  
White Leds ◽  
Light Excitation ◽  
Co Precipitation

A novel red fluoride phosphor BaNbF7:Mn4+ was synthesized by co-precipitation method. Under UV and blue light excitation, this phosphor shows strong ZPL emission intensity at 630 nm and which makes it an attractive red phosphor candidate for WLEDs.

Effects of Sintering Route and Flux on the Luminescence and Morphology of YAG: Ce Phosphors for White Emitting-Light Diodes (LEDs)

2012 ◽  
Vol 236-237 ◽  
pp. 9-15
Author(s):  
Tao Han ◽  
Shi Xiu Cao ◽  
Ming Xing Ma ◽  
Da Chuan Zhu ◽  
Cong Zhao ◽  
...  
Keyword(s):  
White Light ◽  
Potential Application ◽  
Color Temperature ◽  
Precipitation Method ◽  
Photoluminescence Intensity ◽  
White Led ◽  
White Leds ◽  
Chromaticity Coordinates ◽  
Co Precipitation ◽  
Surface Morphologies

YAG:Ce phosphors were synthesized by co-precipitation method. The photoluminescence intensity of samples sintered by the two-step route increases by about 10%, and with 0.5 wt.% NH4Cl added as flux, surface morphologies and size distribution are improved. The white LEDs were fabricated using as-obtained phosphors. It shows natural white light with chromaticity coordinates of (0.3083, 0.3163), color temperature (Tc) of 6886 K, the average CRI of 75, and the luminous efficacy of 85 ml/W. Therefore, The as-obtained YAG:Ce phosphors could be regard to have potential application in white LED 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.

scholarly journals Influence of Cobalt Substitution in LaMnO3 on Catalytic Propylene Oxidation

2021 ◽  
Vol 21 (5) ◽  
pp. 1244
Author(s):  
Teotone Inas Mariano Vaz ◽  
Sridhar Maruti Gurav ◽  
Arun Vithal Salker
Keyword(s):  
Perovskite Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Total Oxidation ◽  
Propylene Oxidation ◽  
Xrd Diffraction ◽  
Structure Morphology ◽  
Cobalt Substitution ◽  
Co Precipitation ◽  
Oxidation Efficiency

Perovskite-type structures LaBO3 with the compositions of LaMn1-xCoxO3 (x = 0.0, 0.3, 0.5, 0.7, and 1.0) were synthesized at 800 °C by a modified co-precipitation precursor technique for total oxidation of propylene, as a model test of the hydrocarbon oxidation reaction. Details concerning the evolution of the crystal structure, morphology, and crystallite size were performed by X-ray diffraction (XRD), Thermo Gravimetry Analysis (TGA)/Differential Scanning Calorimetry (DSC), Fourier Transform Infra-Red (FTIR), Atomic Absorption Spectroscopy (AAS), Scanning Electron Microscopy (SEM), and Electron Spin Resonance (ESR) techniques. All compositions were identified to be single-phase and are indexed to rhombohedral structures. TG/DSC technique evidenced a temperature of 330 °C needed for the precursor as the start point and 800 °C completion for perovskite phase formation. Slight distortion in XRD diffraction peaks was observed on substituting manganese with cobalt in B-site, and new peaks emerged. An attempt has been made to understand the effect of the B-site substitution of Co3+ ions in the lattice of LaMnO3 and their influence on catalytic total propylene oxidation efficiency. These compounds show a considerable increase in the activity of propylene oxidation to carbon dioxide and water and could be explored for hydrocarbon pollution control.

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