Процессы передачи энергии в эвлитите Sr-=SUB=-3-=/SUB=-Y(PO-=SUB=-4-=/SUB=-)-=SUB=-3-=/SUB=-, по отдельности и одновременно легированном ионами Tb-=SUP=-3+-=/SUP=- и Tm-=SUP=-3+-=/SUP=-

In this work the optical spectroscopy and the energy transfer processes involving the Tb3+and Tm3+ ions, have been studied in eulytite double phosphate hosts of the type Sr3Y(PO4)3 doped with various amounts of the two Ln ions. It has been found that several energy transfer and cross-relaxation processes are active in this class of materials, upon excitation in the 5D4 level of Tb, and in the 1G4 one of Tm. In particular, a Tb→Tm transfer of excitation has been found to quench strongly the 5D4 level of Tb. This process occurs with a transfer efficiency increasing from 0.08 to 0.62, for a donor concentration of 2 mol%, and an acceptor concentration increasing from 2 to 15 mol%. The emission spectra are strongly affected by the presence of Tb⟷Tm energy transfer, and Tm→Tm cross relaxation processes.

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Synthesis and properties of diads based on tetra-aryl porphyrins and ruthenium bis-terpyridine-type complexes

Journal of Porphyrins and Phthalocyanines ◽

10.1002/jpp.370 ◽

2001 ◽

Vol 05 (07) ◽

pp. 600-607 ◽

Cited By ~ 21

Author(s):

ISABELLE M. DIXON ◽

JEAN-PAUL COLLIN

Keyword(s):

Energy Transfer ◽

Excited State ◽

Fluorescence Quenching ◽

Emission Spectra ◽

Spectroscopic Properties ◽

Free Base ◽

Strong Electron ◽

Transfer Processes ◽

C Complex

Four diads consisting of a free-base or zinc aryl-porphyrin associated with two ruthenium(II) bis(terdentate) complexes (non-cyclometallated Ru ( N 6) or cylometallated Ru ( N 5 C )) have been synthesized. The strong electron-withdrawing properties of the Ru ( N 6) as compared to the Ru ( N 5 C ) complex have been illustrated by their electrochemical and spectroscopic properties. Emission spectra of the diads and the reference compounds have shown that very efficient fluorescence quenching occurs, probably by energy transfer processes from the porphyrin to the 3MLCT excited state of the ruthenium unit.

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Marine Cyanobacteria Tune Energy Transfer Efficiency in their Light-harvesting Antennae by Modifying Pigment Coupling

10.1101/656173 ◽

2019 ◽

Author(s):

Yuval Kolodny ◽

Hagit Zer ◽

Mor Propper ◽

Shira Yochelis ◽

Yossi Paltiel ◽

...

Keyword(s):

Energy Transfer ◽

Light Harvesting ◽

Vertical Mixing ◽

Photosynthetic Apparatus ◽

Emission Spectra ◽

Energy Transfer Efficiency ◽

Transfer Efficiency ◽

Transfer Energy ◽

Harvesting Process

AbstractPhotosynthetic organisms regulate energy transfer to fit to changes in environmental conditions. The biophysical principles underlying the flexibility and efficiency of energy transfer in the light-harvesting process are still not fully understood. Here we examine how energy transfer is regulatedin-vivo. We compare different acclimation states of the photosynthetic apparatus in a marine cyanobacterial species that is well adapted to vertical mixing of the ocean water column and identify a novel acclimation strategy for photosynthetic life under low light intensities. Antennae rods extend, as expected, increasing light absorption. Surprisingly, in contrast to what was known for plants and predicted by classic calculations, these longer rods transfer energy fasteri.e.more efficiently. The fluorescence lifetime and emission spectra dependence on temperature, at the range of 4-300K, suggests that energy transfer efficiency is tuned by modifying the energetic coupling strength between antennae pigments.

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Energy Transfer and Cross-Relaxation Induced Efficient 2.78 μm Emission in Er3+/Tm3+: PbF2 mid-Infrared Laser Crystal

Crystals ◽

10.3390/cryst11091024 ◽

2021 ◽

Vol 11 (9) ◽

pp. 1024

Author(s):

Jiayu Liao ◽

Qiudi Chen ◽

Xiaochen Niu ◽

Peixiong Zhang ◽

Huiyu Tan ◽

...

Keyword(s):

Energy Transfer ◽

First Principles ◽

Spectroscopic Properties ◽

Transfer Mechanism ◽

Cross Relaxation ◽

Relaxation Processes ◽

Energy Transfer Mechanism ◽

First Principles Calculations ◽

Laser Materials ◽

Mid Infrared

An efficient enhancement of 2.78 μm emission from the transition of Er3+: 4I11/2 → 4I13/2 by Tm3+ introduction in the Er/Tm: PbF2 crystal was grown by the Bridgman technique for the first time. The spectroscopic properties, energy transfer mechanism, and first-principles calculations of as-grown crystals were investigated in detail. The co-doped Tm3+ ion can offer an appropriate sensitization and deactivation effect for Er3+ ion at the same time in PbF2 crystal under the pump of conventional 800 nm laser diodes (LDs). With the introduction of Tm3+ ion into the Er3+: PbF2 crystal, the Er/Tm: PbF2 crystal exhibited an enhancing 2.78 μm mid-infrared (MIR) emission. Furthermore, the cyclic energy transfer mechanism that contains several energy transfer processes and cross-relaxation processes was proposed, which would well achieve the population inversion between the Er3+: 4I11/2 and Er3+: 4I13/2 levels. First-principles calculations were performed to find that good performance originates from the uniform distribution of Er3+ and Tm3+ ions in PbF2 crystal. This work will provide an avenue to design MIR laser materials with good performance.

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Origin of visible and near IR upconversion in Yb3+-Tm3+-Er3+ doped BaMgF4 phosphor through energy transfer and cross-relaxation processes

Optical Materials ◽

10.1016/j.optmat.2019.109511 ◽

2020 ◽

Vol 99 ◽

pp. 109511

Author(s):

Bhushan P. Kore ◽

Ashwini Kumar ◽

Robin E. Kroon ◽

Jacobus J. Terblans ◽

Hendrik C. Swart

Keyword(s):

Energy Transfer ◽

Cross Relaxation ◽

Relaxation Processes ◽

Near Ir

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On the decay time of upconversion luminescence

Nanoscale ◽

10.1039/c8nr10332a ◽

2019 ◽

Vol 11 (11) ◽

pp. 4959-4969 ◽

Cited By ~ 15

Author(s):

Jan Bergstrand ◽

Qingyun Liu ◽

Bingru Huang ◽

Xingyun Peng ◽

Christian Würth ◽

...

Keyword(s):

Energy Transfer ◽

Numerical Simulations ◽

Rate Equation ◽

Decay Time ◽

Upconversion Luminescence ◽

Luminescence Decay ◽

Cross Relaxation ◽

Relaxation Processes ◽

Intermediate States

Numerical simulations based on rate-equation models were performed to investigate how the upconversion luminescence decay is affected by the lifetimes of intermediate states, energy transfer, and cross-relaxation processes.

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Broadband Near-Infrared Luminescence in Lead Germanate Glass Triply Doped with Yb3+/Er3+/Tm3+

Materials ◽

10.3390/ma14112901 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2901

Author(s):

Wojciech A. Pisarski ◽

Joanna Pisarska ◽

Radosław Lisiecki ◽

Witold Ryba-Romanowski

Keyword(s):

Energy Transfer ◽

Near Infrared ◽

Infrared Emission ◽

Relaxation Processes ◽

Lead Germanate ◽

Germanate Glass ◽

Transfer Processes ◽

Infrared Luminescence ◽

Near Infrared Emission ◽

Co Doped

This paper deals with broadband near-infrared luminescence properties of lead germanate glass triply doped with Yb3+/Er3+/Tm3+. Samples were excited at 800 nm and 975 nm. Their emission intensities and lifetimes depend significantly on Er3+ and Tm3+ concentrations. For samples excited at 800 nm, broadband emissions corresponding to the overlapped 3H4 → 3F4 (Tm3+) and 4I13/2 → 4I15/2 (Er3+) transitions centered at 1.45 µm and 1.5 µm was identified. Measurements of decay curves confirm reduction of 3H4 (Tm3+), 2F5/2 (Yb3+) and 4I13/2 (Er3+) luminescence lifetimes and the presence of energy-transfer processes. The maximal spectral bandwidth equal to 269 nm for the 3F4 → 3H6 transition of Tm3+ suggests that our glass co-doped with Yb3+/Er3+/Tm3+ is a good candidate for broadband near-infrared emission. The energy transfer from 4I13/2 (Er3+) to 3F4 (Tm3+) and cross-relaxation processes are responsible for the enhancement of broadband luminescence near 1.8 µm attributed to the 3F4 → 3H6 transition of thulium ions in lead germanate glass under excitation of Yb3+ ions at 975 nm.

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Mechanisms of the energy transfer between thulium ions in tungstate and molybdate crystals

Journal of the Belarusian State University. Physics ◽

10.33581/2520-2243-2021-1-33-40 ◽

2021 ◽

pp. 33-40

Author(s):

Natali V. Gusakova ◽

Maxim P. Demesh ◽

Anatol S. Yasukevich ◽

Anatoliy A. Pavlyuk ◽

Nikolay V. Kuleshov

Keyword(s):

Energy Transfer ◽

Relaxation Process ◽

Emission Spectra ◽

Energy Migration ◽

Cross Relaxation ◽

Laser Generation ◽

Laser Materials ◽

Cross Relaxation Process ◽

The Cross ◽

Hopping Model

In this work, we investigated mechanisms of the energy transfer in Tm : KY(WO4)2, Tm : KLu(WO4)2 and Tm:NaBi(MoO4)2 crystals. Room-temperature absorption and emission spectra were used to determine microparameters of energy migration among thulium ions in the 3H4 and 3F4 excited states in the frames of Förster – Dexter theory. Parameters of cross-relaxation 3H4 + 3H6 → 3F4 + 3F4 and energy migration were obtained via analysis of luminescence decay 3H4 → 3F4 with a hopping model. The parameters describing excitation migration between thulium ions in 3H4 state obtained by two methods were in good agreement. It has been shown that the dipole-dipole mechanism of interaction is responsible for the efficient cross-relaxation process in the crystals under study. The results indicate that the energy migration between 3H4 enhances the cross-relaxation at thulium content more than ∼1.3–1.5 at. % in these laser materials. The obtained values of the migration parameters CDD exceed the values of the cross-relaxation parameters CDA, and the energy transfer in these materials can be described with the hopping model. An efficient cross-relaxation process leads to the relatively high efficiencies of the systems based on these crystals under pumping at 0.8 µm. The dominant process of energy migration between thulium ions in 3F4 excited state makes tungstate and molybdate crystals good candidates for the Ho3+ co-activation for laser generation at 2.1 µm. Parameters obtained in this study can be used for mathematical modeling of laser characteristics.

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