The optical spectrum of UVLED excitation using NTC nanometer particles to replace rare earth doping

MRS Advances ◽  
2019 ◽  
Vol 4 (33-34) ◽  
pp. 1895-1904
Author(s):  
Lihong Su ◽  
Kan Chen ◽  
Yongqiang Liu ◽  
ZiAo Zou ◽  
Lihua Su

Abstract:Ultraviolet light-emitting diodes (UVLEDs) with phosphor materials have considerable advantages over traditional illumination devices. Doping with rare earth ions can modify the optical spectrum of phosphor materials, but rare earths are very expensive. Thus, replacing rare earths with a common material would provide a great potential for the wide application in the future. In this study, we discovered that a novel type of semiconductor nanometre powder, namely manganese cobalt nickel copper oxide (MCNC), is able to emit blue-green wavelength spectrum when exited by 365-400nmUVLED. In addition, MCNC shows less attenuation of luminescence efficiency than other UVLED phosphor materials doped with rare earths with temperature increase. It is thus concluded that MCNC is a promising low-cost material to replace rare earths to adjust the optical spectrum wavelength of UVLED. This is the first time that nano-scale MCNC is reported to possess the property to change the optical spectrum wavelength of UVLED. This provides a new mechanical and nanometer phosphor material without rare earth doping to shift the wavelength spectrum.

2011 ◽  
Vol 335-336 ◽  
pp. 1428-1432 ◽  
Author(s):  
Zhong Wei Pan ◽  
Chang Ma ◽  
Ying Wu Zhang ◽  
Yu Xia Huang ◽  
Xing Lin Chen ◽  
...  

The extraction behavior of five rare earth ions (RE3+) was investigated in ionic liquid (IL) extraction system using 1-butyl-3-methyl-imidazolium hexafluorophosphate ionic liquid ([Bmim]PF6) as extraction solvent and benzoyl acetone (HA) as extractant. The extraction percentage of RE3+ using [Bmim]PF6 was less than 8% without HA. When sufficient HA was included in IL phase, the extraction percentage of RE3+ could be higher than 98%. The extracted species in the RE3+-[Bmim]PF6-HA system was neutral REA3 and the recovery of RE3+ extracted into [Bmim]PF6 can be achieved using the mixture of hydrazine hydrate and ethylenediamine tetraacetic acid (EDTA) as stripping agent. [Bmim]PF6 can be recycled in the experiment.


RSC Advances ◽  
2017 ◽  
Vol 7 (72) ◽  
pp. 45351-45362 ◽  
Author(s):  
Nagaphani Kumar Batchu ◽  
Tom Vander Hoogerstraete ◽  
Dipanjan Banerjee ◽  
Koen Binnemans

Mixtures of rare earths are separation by non-aqueous solvent extraction with two immiscible organic phases.


2014 ◽  
Vol 2 (45) ◽  
pp. 19415-19426 ◽  
Author(s):  
Joris Roosen ◽  
Jeroen Spooren ◽  
Koen Binnemans

Functionalized chitosan–silica hybrid materials were synthesized, characterized and used for adsorption of rare-earth ions. These adsorbents can be used for the separation of mixtures of rare-earths.


2015 ◽  
Vol 361 ◽  
pp. 69-94
Author(s):  
V. Shanker ◽  
D. Haranath ◽  
G. Swati

This article presents a broad review of long persistence (LP) materials that are a special kind of photon energy storage and conversion materials. They are also known as long afterglow phosphors or long decay phosphors (LDP). These phosphors can be readily excited by any ordinary household lamp, sunlight and/or ambient room lights and glow continuously in the dark for hours together without involving any radioactive elements. It is the modifications that are made to crystalline host lattice that exhibit these unusual properties related to persistence due to effective doping of some transition or rare-earth ions. A slight variation in the processing parameters such as type of reducing atmosphere, stoichiometric excess of one or more constituents, the nature of fluxes, and the intentional addition of carbon or rare-earth halides can drastically shift the emission colors and persistence times of the LP phosphors in the visible spectrum. Historically, Cu-doped ZnS phosphor had been a traditional LP material with its afterglow time less than an hour. The emission color of these LP phosphors was confined between green and yellow-green region only. However, synthesis of blue and red-emitting phosphors with long persistence times had been always a challenging task. This review article covers the recent advances in the blue, green and red-emitting LP phosphors/nanophosphors, persistence mechanism involved and the basic problems associated with their luminescence efficiency and persistence times. Modifications to existing nanosynthesis protocols to formulate a nontoxic Green Chemistry Route are also presented.Contents of Paper1. Long Afterglow Phosphors


RSC Advances ◽  
2016 ◽  
Vol 6 (104) ◽  
pp. 102183-102192 ◽  
Author(s):  
Qiongyu Bai ◽  
Zhijun Wang ◽  
Panlai Li ◽  
Shuchao Xu ◽  
Ting Li ◽  
...  

Generally, luminescent properties of rare earth ions doped host can be tuned by controlling the host composition, that is, when substituted for different cations of host, the rare earths ions can present different characteristics.


RSC Advances ◽  
2016 ◽  
Vol 6 (5) ◽  
pp. 3440-3445 ◽  
Author(s):  
Yunhua Yao ◽  
Cheng Xu ◽  
Ye Zheng ◽  
Chengshuai Yang ◽  
Pei Liu ◽  
...  

Improving up-conversion luminescence efficiency of rare-earth ions is always a research hotspot because of its important applications in laser source, color display, photoelectric conversion and multiplexed biolabeling.


2003 ◽  
Vol 770 ◽  
Author(s):  
Maria E. Castagna ◽  
Salvatore Coffa ◽  
Mariantonietta Monaco ◽  
Anna Muscara' ◽  
Liliana Caristia ◽  
...  

AbstractWe report on the fabrication and performances of the most efficient Si-based light sources. The devices consist of MOS structures with erbium (Er) implanted in the thin gate oxide. The devices exhibit strong 1.54 μm electroluminescence at 300K with a 10% external quantum efficiency, comparable to that of standard light emitting diodes using III-V semiconductors. Emission at different wavelenghts has been achieved incorporating different rare earths (Ce, Tb, Yb, Pr) in the gate dielectric. The external quantum efficiency depends on the rare earth ions incorporated and ranges from 10% (for an Tb doped MOS) to 0.1% (for an Yb doped MOS). RE excitation is caused by hot electrons impact and oxide wearout limits the reliability of the devices. Much more stable light emitting MOS devices have been fabricated using Er-doped SRO (Silicon Rich Oxide) films as gate dielectric. These devices show a high stability, with an external quantum efficiency reduced to 0.2%. In these devices Er pumping occurs part by hot electrons and part by energy transfer from the Si nanostructures to the rare earth ions, depending by Si excess in the film. Si/SiO2 Fabry-Perot microcavities have been fabricated to enhance the external quantum emission along the cavity axis and the spectral purity of emission from the films that are used as active media to realize a Si based RCLED (resonant cavity light emitting diode). These structures are realized by chemical vapour deposition on a silicon substrate. The microcavities are tuned at different wavelengths: 540nm, 980nm and 1540nm (characteristic emission wavelengths respectively for Tb, Yb and Er). The reflectivity of the microcavities is of 97% and the quality factor ranges from 60 (for the cavity tuned at 980nm) to 95 (for the cavities tuned at 540nm and 1540nm).


2014 ◽  
Vol 2 (21) ◽  
pp. 4297-4303 ◽  
Author(s):  
T. Ogi ◽  
H. Iwasaki ◽  
A. B. D. Nandiyanto ◽  
F. Iskandar ◽  
W.-N. Wang ◽  
...  

A novel direct white light emitting phosphor material was prepared from rare-earth free precursor solution.


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