Highly Efficient and Thermally Stable Eu2+-Doped Ca9Nd(PO4)7 Phosphor for Near-Ultraviolet White-Emission LED Applications

2021 ◽  
Vol 21 (12) ◽  
pp. 5859-5866
Author(s):  
Jian Zhou ◽  
Si-Li Ren
Keyword(s):  
Room Temperature ◽  
Green Emission ◽  
Color Temperature ◽  
Multipole Interaction ◽  
Interaction Radius ◽  
Promising Alternative ◽  
Quenching Effect ◽  
Near Ultraviolet ◽  
Great Performance ◽  
Concentration Quenching Effect

Various Eu2+-based Ca9Nd(PO4)7 (CNP:xEu2+, with different x values) materials are prepared via facile solid-state reaction. Their crystal structures are investigated in detail by means of the Rietveld refinement. The structure of CNP:Eu2+ with a trigonal lattice is analogous to that of β-Ca3(PO4)2. Therefore, Eu2+ ions tend to incorporate calcium sites in the host. All the obtained samples can be excited using near ultraviolet (nUV) light to present blue-green emission. An optimal dopant concentration is verified at x = 0.8 with a large critical interaction radius (11.21 Å). The mechanism of the concentration quenching effect is assigned to the multipole-multipole interaction. CNP:xEu2+ possesses a short decay lifetime of ∼60 μs and can endure severe working conditions thanks to its great thermal stability. The relative photoluminescence (PL) intensity of CNP:0.8Eu2+ can retain 84.75% of the pristine intensity measured at room temperature, and the relative intensity remains as high as 69.97% at 423 K. The CNP:Eu2+ phosphors also show great performance in the WLED demonstration. The correlated color temperature (CCT) of the prototype device is 3404 K, with an extremely high Ra (97.6). Therefore, CNP:xEu2+ could be regarded as a promising alternative to blue green phosphors in nUV chip-based WLED applications.

Investigation of Er3+ Doped in Na2O-Al2O3-BaO-CaO-Sb2O3-B2O3 -SiO2 Glasses: Physical, Optical and Visible Luminescence Properties

2014 ◽  
Vol 974 ◽  
pp. 86-90
Author(s):  
S. Tuscharoen ◽  
N. Chanthima ◽  
J. Kaewkhao
Keyword(s):  
Molecular Weight ◽  
Green Emission ◽  
Concentration Quenching ◽  
Luminescence Properties ◽  
Doping Content ◽  
Quenching Effect ◽  
Visible Luminescence ◽  
Additional Doping ◽  
Glass Matrices ◽  
Concentration Quenching Effect

In this work, Na2O-Al2O3-BaO-CaO-Sb2O3-B2O3-SiO2 glasses doped with Er3+ was prepared and investigated for their physical, optical and visible luminescence properties. The increases in density, refractive index and molar volume of the glasses with additional doping content of Er2O3 into the network were due to a higher molecular weight and polarizability of Er2O3 in comparison with the glass former (SiO2 and B2O3). Ten absorption peaks were observed as a nature of Er3+ absorption in glass matrices. The glass exhibited four emission transitions which were assigned to 4F5/2→4I15/2 (460 nm), 4F7/2→4I15/2 (487 nm), 2H11/2→4I15/2 (522 nm) and 4S3/2→4I15/2 (545 nm) transitions. The strongest intensity was the green emission at 522 nm. The luminescence intensity was found to increase with Er2O3 content up to 4 mol% and it was decreased for higher Er2O3 contents due to concentration quenching effect.

Luminescence Properties of Er3+ Ions in Bismuth Borophosphate Glasses

2016 ◽  
Vol 675-676 ◽  
pp. 351-354
Author(s):  
Natthakridta Chanthima ◽  
Jakrapong Kaewkhao
Keyword(s):  
Near Infrared ◽  
Emission Spectra ◽  
Green Emission ◽  
Concentration Quenching ◽  
Luminescence Spectra ◽  
Quenching Effect ◽  
Borophosphate Glasses ◽  
Uv Visible ◽  
Quenching Method ◽  
Concentration Quenching Effect

Er3+ ions doped bismuth borophosphate glasses are prepared in different concentration by the conventional melting-quenching method at 1200 °C. Physical properties, absorption and luminescence spectra under visible excitation are investigated. The results showed that density of glasses tended to decrease with increasing the concentration of Er2O3. While, the molar volume of glasses tended to increase with increasing the concentration of Er2O3. The optical absorption spectra were clearly observed in ultraviolet (UV), visible light (VIS) and near infrared (NIR) region. Visible emission spectra have been recorded by exciting the glass samples at 326 nm. The strongest intensity was the green emission at 521 nm. The luminescence intensity was found to increase with Er2O3 content up to 0.8 mol% and it was decreased for higher Er2O3 contents due to concentration quenching effect.

Modeling of thermoluminescence in SrY2O4:Eu3+and their concentration quenching effect

Optik ◽  
2021 ◽  
Vol 232 ◽  
pp. 166607
Author(s):  
Amirouche Bouremani ◽  
Dahane Kadri ◽  
Ahmed Kadari ◽  
Vikas Dubey
Keyword(s):  
Concentration Quenching ◽  
Quenching Effect ◽  
Concentration Quenching Effect

Notizen:Phosphorescence Decay in Thallium-Doped Ammonium Chloride

1978 ◽  
Vol 33 (10) ◽  
pp. 1241-1242 ◽  
Author(s):  
S. Chaudhari ◽  
T. R. Joshi ◽  
R. V. Joshi
Keyword(s):  
Aqueous Solution ◽  
Ammonium Chloride ◽  
Mechanical Treatment ◽  
Room Temperature ◽  
Host Lattice ◽  
Luminescence Decay ◽  
Decay Rates ◽  
Negative Ion ◽  
Ultraviolet Emission ◽  
Near Ultraviolet

Abstract The phosphorescence decay rates of thallium-doped ammonium chloride (NH4Cl:Tl) phosphors, prepared by crystallization from aqueous solution, have been studied at room temperature for near-ultraviolet emission. The effects of impurity concentration as well as thermal and/or mechanical treatment on the decay rates have been examined. Phosphorescence centres consisting of a Tl+ion and a nearby negative ion vacancy are suggested to be responsible for the observed luminescence decay. The changes in the decay characteristics after pretreatments are explained on the basis of the location of the centres in normal and distorted regions of the host lattice.

Room-temperature near-ultraviolet electroluminescence from a linear silicon chain

1997 ◽  
Vol 71 (23) ◽  
pp. 3326-3328 ◽  
Author(s):  
Chien-Hua Yuan ◽  
Satoshi Hoshino ◽  
Seiji Toyoda ◽  
Hiroyuki Suzuki ◽  
Michiya Fujiki ◽  
...  
Keyword(s):  
Room Temperature ◽  
Near Ultraviolet

Ester-functionalized thermally activated delayed fluorescence materials

2021 ◽  
Author(s):  
Hiroshi Tasaki ◽  
So Shikita ◽  
In Seob Park ◽  
Takuma Yasuda
Keyword(s):  
Delayed Fluorescence ◽  
Concentration Quenching ◽  
Thermally Activated Delayed Fluorescence ◽  
Quenching Effect ◽  
Thermally Activated ◽  
Concentration Quenching Effect ◽  
Neat Films

A family of thermally activated delayed fluorescence (TADF) materials functionalized with carboxylate esters is presented herein. Owing to their suppressed concentration-quenching effect in neat films, these ester-functionalized TADF emitters could...

Green Generation by Single-Pass Frequency-Doubling in a Periodically Poled MgO:LiNbO3 at Room Temperature

2012 ◽  
Vol 622-623 ◽  
pp. 1258-1261
Author(s):  
Hong Bo An ◽  
Bing Hua Su ◽  
Li Hong Niu ◽  
Jun Wen Xue
Keyword(s):  
Room Temperature ◽  
Continuous Wave ◽  
Second Harmonic ◽  
Frequency Doubling ◽  
Green Emission ◽  
Simulation Data ◽  
Periodically Poled ◽  
Single Pass ◽  
Narrow Bandwidth ◽  
Rayleigh Length

122mW green emission at 532.3nm with a conversion efficiency of 1.2% was measured by single-pass second-harmonic generation in a 10mm long periodically poled MgO:LiNbO3 (MgO:PPLN) crystal is reported. A continuous-wave Yb-doped fiber laser operating at 1064.6nm with narrow bandwidth of 0.1nm is used as pumping source. The experimental temperature acceptance bandwidth ΔT=4.6°C is a little higher than the simulation data of 4°C. Output power instabilities or variations of the green beam pattern were not observed during experiments. In this work, the optimized efficiency was achieved when the waist located at the center of MgO:PPLN and Rayleigh length equal to its length, and the lens’ location in the system was calculated.

A Promising Alternative for Sustainable and Highly Efficient Solar‐Driven Deuterium Evolution at Room Temperature by Photocatalytic D 2 O Splitting

ChemSusChem ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2935-2939 ◽  
Author(s):  
Gongchang Zeng ◽  
Heping Zeng ◽  
Lishan Niu ◽  
Jiayi Chen ◽  
Ting Song ◽  
...  
Keyword(s):  
Room Temperature ◽  
Promising Alternative ◽  
Highly Efficient

Influence of Sensitizer Concentration on the Upconversion Luminescence of NaYF4: Yb3+, Er3+ Nanoparticles

2012 ◽  
Vol 510 ◽  
pp. 609-613 ◽  
Author(s):  
Jun Wei Zhao ◽  
Dong Mei Shi ◽  
Ying Gang Zhao ◽  
Xiang Gui Kong
Keyword(s):  
Room Temperature ◽  
Doping Concentration ◽  
Sodium Citrate ◽  
Upconversion Luminescence ◽  
Green Emission ◽  
Cross Relaxation ◽  
The Cross ◽  
Hydrothermal Methods ◽  
Sensitization Effect

A series of NaYF4: Yb3+, Er3+ nanoparticles with different doping concentration were successfully prepared by the combination of coprecipitation and hydrothermal methods using sodium citrate as chelator. Upconversion luminescence can be observed in all of the samples at room temperature. Fixed the Er3+ concentration with 1 mol% unchanged, the effect of the Yb3+ concentration on the upconversion luminescence of NaYF4: Yb3+, Er3+ samples were studied when the doped Yb3+ concentrations were 0 mol%, 1 mol%, 2 mol%, 5 mol%, 10 mol% and 20 mol%, respectively. As increasing the Yb3+ concentration, the total intensity of the upconversion luminescence of the samples is increasing while the ratio of red to green emission increases firstly and then decreases. The maximum ratio value is 22.1 when the Yb3+ concentration is 10 mol%. It is found that the cross relaxation and cooperative sensitization effect are the reasons for the phenomenon above.

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