Improvement of luminescence properties of rubidium vanadate, RbVO3, phosphors by erbium doping in the crystal lattice

2017 ◽  
Vol 41 (12) ◽  
pp. 4788-4792 ◽  
Author(s):  
S. W. Kim ◽  
T. Hasegawa ◽  
M. Muto ◽  
A. Toda ◽  
T. Kaneko ◽  
...  
Keyword(s):  
Crystal Lattice ◽  
Emission Intensity ◽  
Thermal Quenching ◽  
Luminescence Properties ◽  
Erbium Doping ◽  
Quenching Effect

The thermal quenching effect of RbVO3 phosphor was effectively improved by Er3+ doping into the lattice, as a result, the emission intensity of the phosphor was successfully enhanced.

Enhancing negative thermal quenching effect via low-valence doping in two-dimensional confined core–shell upconversion nanocrystals

2018 ◽  
Vol 6 (43) ◽  
pp. 11587-11592 ◽  
Author(s):  
Lei Lei ◽  
Jienan Xia ◽  
Yao Cheng ◽  
Yuansheng Wang ◽  
Gongxun Bai ◽  
...  
Keyword(s):  
Emission Intensity ◽  
Thermal Quenching ◽  
Core Shell ◽  
Two Dimensional ◽  
Quenching Effect ◽  
Upconversion Nanocrystals

Doping low-valence ions in core–shell NC is applied to improve negative thermal quenching effect. With the increase in temperature from 293 to 413 K, the UC emission intensity of 20Yb/2Er : NaGdF4 (12 nm) increases by 2.2 times, whereas that of NaGdF4@20Ca/20Yb/2Er: NaGdF4 (11 nm) increases by 10.9 times.

scholarly journals The Effect of Ionising Radiation on the Luminescence Properties of Fluoroperovskites

2021 ◽  
Author(s):  
◽  
Joseph Schuyt
Keyword(s):  
Energy Levels ◽  
Thermal Quenching ◽  
Ionising Radiation ◽  
Luminescence Properties ◽  
Readout System ◽  
Tissue Equivalent ◽  
Potential Applications ◽  
Radiation Induced ◽  
Medical Dosimetry ◽  
Physical Phenomena

<p>The luminescence of crystalline compounds can be used to monitor many physical phenomena, including doses of ionising radiation. Optically stimulated luminescence (OSL), thermoluminescence (TL), and radiophotoluminescence (RPL) have been successfully employed in dosimetry. However, few materials possess both the structural and luminescence properties required for medical dosimetry. This thesis aimed to investigate the luminescence features of the class of compounds known as fluoroperovskites. Emphasis was placed on studying the effects of irradiation on the luminescence properties, such that the compounds could be evaluated regarding potential applications in clinical dosimetry. Samples were primarily characterised using photoluminescence (PL), radioluminescence (RL), OSL, RPL, TL, and transmittance spectroscopy.  OSL was observed in the majority of samples due to the existence of electron trapping F-type centres. F-centre/Mn complexes were observed in all AMgF3:Mn compounds after irradiation and the energy levels of the complexes in each compound were experimentally determined. The most promising potential dosimeter host material was the near tissue-equivalent NaMgF3. When doped with Mn2+, the compound exhibited RPL via the formation of F-centre/Mn complexes and OSL via several trapping centres. The RPL could be probed independently to the OSL such that the compound could function as a hybrid OSL/RPL dosimeter. In the NaMgF3:Ln compounds, RPL occurred via the radiation-induced reduction Ln3+ → Ln2+ for Ln = Sm, Dy, and Yb. The reduction Sm3+ → Sm2+ was highly stable and could be non-destructively probed independently to the OSL. The Sm doped compound also exhibited radiation-induced conductivity that could be coupled with the RL, such that the compound could function as a real-time hybrid optical/electrical dosimeter. Charge kinetics, thermal quenching, and binding energy models were developed and applied to the compounds.   Finally, a two-dimensional readout system was designed and constructed. The capabilities of the system were evaluated using the OSL of NaMgF3:Eu and NaMgF3:Mn. Sensitivities to doses from < 10 mGy to > 1 Gy were obtained along with sub-millimetre spatial resolutions.</p>

Luminescence properties of Mn4+ with high 2Eg level energy in the polyfluoride Na3Li3Sc2F12

2020 ◽  
Vol 49 (33) ◽  
pp. 11613-11617
Author(s):  
Hong Li ◽  
Yan Liu ◽  
Shu Tang ◽  
Lijun Luo ◽  
Qiang Zhou ◽  
...  
Keyword(s):  
Quantum Efficiency ◽  
External Quantum Efficiency ◽  
Thermal Quenching ◽  
Luminescence Properties ◽  
Level Energy ◽  
Red Emission ◽  
White Leds ◽  
Red Emitting Phosphor

Red-emitting phosphor Na3Li3Sc2F12:Mn4+ with the high 2Eg level energy shows intensive red emission accompanied with the high external quantum efficiency and thermal-quenching resistance for warm white LEDs.

PREPARATION AND LUMINESCENCE PROPERTIES OF Eu2+-ACTIVATED Ba-Six-O-N PHOSPHORS

2010 ◽  
Vol 24 (15n16) ◽  
pp. 3221-3225 ◽  
Author(s):  
RUILI ZHANG ◽  
MANAKA NUMATA ◽  
TOMONORI MAEDA ◽  
YUJI AKAZAWA ◽  
KEI-ICHIRO MURAI ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Emission Intensity ◽  
Visible Region ◽  
Wavelength Region ◽  
Green Emission ◽  
Main Phase ◽  
Luminescence Properties ◽  
White Led

A series of oxonitridosilicates phosphors Ba - Si x - O - N / Eu 2+ ( x = Si / Ba =1~8, 5atom% Eu 2+) were synthesized using traditional solid-state reaction. For x = 2~8, the main phase of the obtained samples was Ba 3 Si 6 O 12 N 2. All Ba - Si x - O - N / Eu 2+( x = 1~8) materials could be efficiently excited in the UV to visible region(310~450 nm ) and had a green emission at 508~522 nm , making them attractive as conversion phosphors for white LED applications. With increasing x values, the emission peaks shifted to the longer wavelength region, while the emission intensity had a maximum at x = 6. The influence of the firing times was also discussed, after twice fired, there was a tendency of single-phased formed of the obtained materials and the emission intensity was greatly improved.

A narrow-band blue emitting phosphor Ca8Mg7Si9N22:Eu2+ for pc-LEDs

2019 ◽  
Vol 7 (13) ◽  
pp. 3730-3734 ◽  
Author(s):  
Chao Li ◽  
Xiao-Ming Wang ◽  
Feng-Feng Chi ◽  
Zu-Pei Yang ◽  
Huan Jiao
Keyword(s):  
Emission Intensity ◽  
Room Temperature ◽  
Narrow Band ◽  
Blue Emission ◽  
Thermal Quenching ◽  
Unit Cell ◽  
Photoluminescence Emission ◽  
Space Group

Ca8Mg7Si9N22 crystallizes in a tetragonal space group P42/nmc (No. 137) with a unit cell of a = 7.3271(11) Å and c = 10.336(2) Å. Ca8Mg7Si9N22:Eu2+ shows a narrow-band blue emission peaking at 400 nm with an intriguing bandwidth ∼34 nm and shows remarkably high thermal quenching resistance, maintaining 92% photoluminescence emission intensity at 420 K and 75% at 700 K of that measured at room temperature.

Thermoluminescence study on TlGaSSe layered single crystals

2014 ◽  
Vol 28 (16) ◽  
pp. 1450133 ◽  
Author(s):  
Serdar Delice ◽  
Nizami M. Gasanly
Keyword(s):  
Single Crystals ◽  
Heating Rate ◽  
Thermal Quenching ◽  
Activation Energies ◽  
Temperature Peak ◽  
Heating Rates ◽  
Quenching Effect ◽  
Defect Centers ◽  
General Order ◽  
Maximum Temperatures

The defect centers in TlGaSSe single crystals have been investigated by performing thermoluminescence (TL) measurements with various heating rates between 0.5 K/s and 1.0 K/s in the temperature range of 10–180 K. The TL spectra, with peak maximum temperatures at 39 K and 131 K, revealed the existences of two defect levels. Curve fitting, initial rise and peak shape methods were used to determine the activation energies of two defect centers. The experimental results also showed that the trapping process was dominated by second-order kinetics for the trap related with low temperature peak while the general order (mixed order) kinetics was dominant for the trap donated to high temperature peak. Furthermore, heating rate dependences and traps distributions were studied for two defect centers separately. Thermal quenching effect dominates the behavior of these defects as the heating rate is increased. Also, quasi-continuous distributions were established with the increase of the activation energies from 16 meV to 27 meV and from 97 meV to 146 meV for the traps associated with the peaks observed at low and high temperatures, respectively.

Electroluminescence of Yb-Doped InP

1994 ◽  
Vol 358 ◽  
Author(s):  
A. K. Alshawa ◽  
H. J. Lozykowski ◽  
I. Brown
Keyword(s):  
Emission Intensity ◽  
Thermal Quenching ◽  
Impact Excitation ◽  
Electroluminescence Spectrum ◽  
Excitation Mechanism ◽  
Natural Logarithm ◽  
Straight Line ◽  
Decay Times ◽  
Line Characteristic ◽  
Electroluminescence Intensity

ABSTRACTDetailed experimental and theoretical studies of the electroluminescence excitation mechanism of Yb3+ in InP are presented. The electroluminescence spectra and the kinetics of Yb implanted InP were investigated under pulsed and dc excitations at temperatures over the range 9 - 70 K. The electroluminescence spectrum of the 4f transitions 2F5/2 - 2F7/2,, at 9 K, consists of a peak at 1001 nm and broader peaks in the spectral range between 1003 nm and 1010 nm. The intensity and current versus voltage characteristics have been recorded. The emission intensity increased linearly with current and started to saturate at high currents. The plot of the natural logarithm of intensity versus V−1/2 shows a straight line characteristic over three orders of emission intensity, showing that the direct impact excitation mechanism is a dominant process. At low temperature, the rise and decay times of the 1001 nm emission line were 9.63 µs and 10.50 µs, respectively. The thermal quenching energy, EA, was found to be 100 meV for both the electroluminescence intensity and the decay time.

scholarly journals Photoluminescent Properties of Hydrogenated Amorphous Silicon Oxide Powders

2002 ◽  
Vol 17 (5) ◽  
pp. 977-980 ◽  
Author(s):  
Wei-Fang Su ◽  
Hong-Ru Guo
Keyword(s):  
Amorphous Silicon ◽  
Silicon Oxide ◽  
Hydrogenated Amorphous Silicon ◽  
Thermal Quenching ◽  
Amorphous Semiconductors ◽  
Electronic Density ◽  
Quenching Effect ◽  
Oxide Powders ◽  
Amorphous Silicon Oxide ◽  
Hydrogenated Amorphous

The photoluminescence properties of hydrogenated amorphous silicon oxide powder SiO0.92H0.53 were investigated. The powder was prepared by reacting lithium with trichlorosilane in tetrahydrofuran. The luminescence peak energy was located between 1.0 and 1.61 eV. The samples were treated under different conditions such as annealing, hydrolysis, and hydrolysis plus HF etching. The changes of the photoluminescent intensity and location on the treated powders can be explained by the electronic density of state model of amorphous semiconductors. The temperature dependence of luminescence properties of the powders can be described by the relationship of thermal quenching effect: ln[Io/I(T) – 1] = ED/Eo = T/To at temperatures between 100 and 300 K.

Luminescence Properties of Er3+/Tm3+-Doped Ga2O3-Bi2O3-PbO-GeO2 System Glasses

2011 ◽  
Vol 399-401 ◽  
pp. 982-986
Author(s):  
Jin Liu ◽  
Dong Mei Shi ◽  
Ying Gang Zhao ◽  
Xiao Feng Wang
Keyword(s):  
Emission Intensity ◽  
Near Infrared ◽  
Emission Spectra ◽  
Upconversion Emission ◽  
Infrared Emission ◽  
Optical Devices ◽  
Luminescence Properties ◽  
Red Emission ◽  
Fiber Optical ◽  
Near Infrared Emission

The visible and near infrared emission spectra of Er3+/Tm3+-doped Ga2O3-Bi2O3-PbO-GeO2(GBPG) glasses excited at 808 nm are experimentally investigated. The results reveal that 1.53 µm emission were enhanced with an increase of Er3+concentration. Furthermore, the incorporation of Er3+into Tm3+-doped systems has also resulted in intense 522, 545 and 693nm upconversion emission intensity and an weak 660 nm red emission. The possible mechanism and related discussions on this phenomenon have been presented. The results show that Er3+/Tm3+-codoped GBPG glass may be a promising materials for developing laser and fiber optical devices.

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