scholarly journals Insight into Eu redox and Pr3+ 5d emission in KSrPO4 by VRBE scheme construction

2018 ◽  
Vol 47 (2) ◽  
pp. 306-313 ◽  
Author(s):  
Rongfu Zhou ◽  
Litian Lin ◽  
Chunmeng Liu ◽  
Pieter Dorenbos ◽  
Ye Tao ◽  
...  
Keyword(s):  
Energy Levels ◽  
Thermal Quenching ◽  
Redox Properties ◽  
Insight Into

The redox properties of Eu, the 5d energy levels of Pr3+ and the thermal quenching characteristics of Ce3+ and Eu2+ luminescence are understood through the KSrPO4 structure and the VRBE scheme.

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>

Experimental insight into the thermal quenching of the Tb3+ ion’s green photoluminescence in CaWO4 host

2019 ◽  
Vol 58 (11) ◽  
pp. 110909
Author(s):  
Leipeng Li ◽  
Feng Qin ◽  
Yuan Zhou ◽  
Jipeng Miao ◽  
Zhiguo Zhang
Keyword(s):  
Thermal Quenching ◽  
Green Photoluminescence ◽  
Insight Into

scholarly journals Functionalized branched EDOT-terthiophene copolymer films by electropolymerization and post-polymerization “click”-reactions

2015 ◽  
Vol 11 ◽  
pp. 335-347 ◽  
Author(s):  
Miriam Goll ◽  
Adrian Ruff ◽  
Erna Muks ◽  
Felix Goerigk ◽  
Beatrice Omiecienski ◽  
...  
Keyword(s):  
Energy Levels ◽  
Contact Angles ◽  
Redox Properties ◽  
Dipolar Cycloaddition ◽  
Surface Polarity ◽  
Water Contact ◽  
Click Reactions ◽  
Copolymer Films ◽  
Post Functionalization

The electrocopolymerization of 3,4-ethylenedioxythiophene (EDOT) with the branched thiophene building block 2,2′:3′,2″-terthiophene (3T) is presented as a versatile route to functional polymer films. Comparisons to blend systems of the respective homopolymers PEDOT and P3T by in situ spectroelectrochemistry and Raman spectroscopy prove the successful copolymer formation and the access to tailored redox properties and energy levels. The use of EDOT-N3 as co-monomer furthermore allows modifications of the films by polymer analogous reactions. Here, we exemplarily describe the post-functionalization with ionic moieties by 1,3-dipolar cycloaddition (“click”-chemistry) which allows to tune the surface polarity of the copolymer films from water contact angles of 140° down to 40°.

Novel La3GaGe5O16 : Mn4+based deep red phosphor: a potential color converter for warm white light

RSC Advances ◽  
2015 ◽  
Vol 5 (110) ◽  
pp. 90499-90507 ◽  
Author(s):  
Shaoan Zhang ◽  
Yihua Hu ◽  
He Duan ◽  
Li Chen ◽  
Yinrong Fu ◽  
...  
Keyword(s):  
Activation Energy ◽  
White Light ◽  
Thermal Quenching ◽  
Temperature Dependent ◽  
Quenching Temperature ◽  
Red Phosphor ◽  
Warm White Light ◽  
Relative Emission Intensity ◽  
Insight Into ◽  
Color Converter

We gained insight into the temperature-dependent relative emission intensity of La3GaGe5O16: Mn4+phosphor, and the luminescence quenching temperature and the activation energy for thermal quenching (ΔE) were obtained.

scholarly journals Insight into the Thermal Quenching Mechanism for Y3Al5O12:Ce3+ through Thermoluminescence Excitation Spectroscopy

2015 ◽  
Vol 119 (44) ◽  
pp. 25003-25008 ◽  
Author(s):  
Jumpei Ueda ◽  
Pieter Dorenbos ◽  
Adrie J. J. Bos ◽  
Andries Meijerink ◽  
Setsuhisa Tanabe
Keyword(s):  
Thermal Quenching ◽  
Quenching Mechanism ◽  
Insight Into

scholarly journals Effective Markovian description of decoherence in bound systems

2014 ◽  
Vol 92 (2) ◽  
pp. 168-178 ◽  
Author(s):  
A.S. Sanz
Keyword(s):  
Degrees Of Freedom ◽  
Energy Levels ◽  
Dynamical Process ◽  
Initial State ◽  
Physical Mechanisms ◽  
State Diffusion ◽  
Decoherence Rate ◽  
Quantum State Diffusion ◽  
Insight Into ◽  
Good Agreement

Effective descriptions accounting for the evolution of quantum systems that are acted on by a bath are desirable. As the number of bath degrees of freedom increases and full quantum simulations turn out computationally prohibitive, simpler models become essential to understand and gain an insight into the main physical mechanisms involved in the system dynamics. In this regard, vibrational decoherence of an I2 diatomics is tackled here within the framework of Markovian quantum state diffusion. The I2 dynamics are analyzed in terms of an effective decoherence rate, Λ, and the specific choice of the initial state, in particular, Gaussian wave packets and two-state superpositions. It is found that, for Markovian baths, the relevant quantity regarding decoherence is the product of friction (η) and temperature (T); there is no distinction between varying one or the other. It is also observed that decoherence becomes faster as the energy levels involved in the system state correspond to higher eigenvalues. This effect is due to a population redistribution during the dynamical process and an eventual irreversible loss of the initial coherence. These results have been compared with those available in the literature from more detailed semiclassical IVR simulations, finding a good agreement.

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>

Photoluminescence Study of Energy Transfer Processes in Erbium Doped AlxGal−xAs Grown by MBE

1993 ◽  
Vol 301 ◽  
Author(s):  
Tong Zhang ◽  
J. Sun ◽  
N.V. Edwards ◽  
D.E. Moxey ◽  
R.M. Kolbas ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Energy Levels ◽  
Coupling Efficiency ◽  
Thermal Quenching ◽  
Energy Bands ◽  
Doped Semiconductors ◽  
Co Doping ◽  
Erbium Ions ◽  
Erbium Doped ◽  
First Time

ABSTRACTSharp photoluminescence from the intra-4f shell of Er3+ is observed from erbium doped AlxGal-xAs (0 ≤x ≤ 1) grown by molecular beam epitaxy. The intensity of the luminescence from the erbium is strongly dependent on the aluminum composition with a maximum at x ≈ 0.6. We will present a model that explains the variation in intensity based on the energy transfer coupling efficiency between the host semiconductor and the optically active erbium ions. The coupling efficiency is dominated by the alignment or misalignment of the erbium energy levels with the energy bands of the host semiconductor and by the excess carrier lifetime in the host. The data and model, which are presented here for the first time, are consistent with our previous work on the effects of co-doping with Be or Si and with other workers' measurements of thermal quenching in rare earth doped semiconductors.

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