Spectral-luminescent effects in heterometallic complexes of crown-porphyrins

New complexes of ytterbium with porphyrins containing crown- and other oxygen-containing cyclic substituents were obtained. The absorption, excitation, ligand luminescence and 4f-luminescence spectra have been investigated. It has been shown that 4f-luminescence of ytterbium Yb ( III ) ions was a result of the intramolecular energy transfer from the triplet level of the ligands to the resonance 2F5/2 level of Yb ( III ). It has been also established that in presence of alkali metal Na , K and Cs the dimer complexes (sandwich-type) of ytterbium-crown-porphyrin were formed. Molecular luminescence of the porphyrin matrix was quenched completely in these dimers, but at the same time the quantum yield and lifetime of 4f-luminescence increase in the complexes.

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Enhanced Luminescence of Terbium Complexes with 2,3-Pyrazinedicarboxylate by Y(III) Doping

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.750-752.1007 ◽

2013 ◽

Vol 750-752 ◽

pp. 1007-1010

Author(s):

Ai Ling Wang ◽

Hai Xia Zhang ◽

Kai Kong ◽

Huan Huan Li ◽

Hua Wang ◽

...

Keyword(s):

Energy Transfer ◽

Lanthanide Complexes ◽

The Self ◽

Lanthanide Ions ◽

Quantum Yields ◽

Luminescence Spectra ◽

Intramolecular Energy Transfer ◽

Enhanced Luminescence ◽

Yttrium Complexes ◽

Terbium Complexes

Ten kinds of terbium doped inert yttrium complexes with 2,3-pyrazinedicarboxylate (2,3-pzdc2-) have been synthesized. Characterization results indicate that the complexes have the compositions of Tb (pzdc)1.55H2O and TbxYy(pzdc)1.55H2O (x:y=0.10:0.90; 0.20:0.80; 0.30:0.70; 0.40:0.60; 0.60:0.40; 0.70:0.30; 0.80:0.20; 0.90:0.10). IR spectra show that the lanthanide ions coordinate with the carboxylic oxygen atoms and nitrogen atoms of the ligands. Luminescence spectra show that the Y(III) ions can remarkably increase the luminescent intensities of terbium complexes. And Tb0.7Y0.3(pzdc)1.55H2O exhibits the strongest luminescent emission. Furthermore, the doped lanthanide complexes show longer luminescence lifetimes and higher quantum yields. The enhanced luminescence efficiencies of Tb3+ions in the doped complexes may result from intramolecular energy transfer as well as the decrease of the self-quench of the Tb3+ions induced by the doped Y(III) ions.

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Influence of chemical structure of branched and dendritic organosilicon luminophores on their optical and thermal properties

Organic Photonics and Photovoltaics ◽

10.1515/oph-2017-0001 ◽

2017 ◽

Vol 5 (1) ◽

pp. 1-8 ◽

Cited By ~ 5

Author(s):

Oleg V. Borshchev ◽

Elena A. Kleymyuk ◽

Nikolay M. Surin ◽

Evgeniya A. Svidchenko ◽

Yuriy V. Fedorov ◽

...

Keyword(s):

Energy Transfer ◽

Thermal Properties ◽

Quantum Yield ◽

Decay Time ◽

Extinction Coefficient ◽

Chemical Structure ◽

High Efficiency ◽

Intramolecular Energy Transfer ◽

Antenna Effect ◽

Complex Molecules

AbstractSynthesis and investigation of optical and thermal properties of a homologous series of highly luminescent nanostructured organosilicon luminophores (NOLs) containing different donor to acceptor ratio (D:A) are reported. Each of the NOL consists of a 1,4-bis(5-phenylthienyl-2-yl)benzene (PTPTP) acceptor unit and four, six or twelve 2,2′-bithienyl donor fragments connected to each other through two or six silicon atoms. These complex molecules show a “molecular antenna” effect with high efficiency of intramolecular energy transfer about 97-98% combined with excellent photoluminescence (PL) quantum yield of 84-91% and fast PL decay time of 0.90-0.95 ns. A significant increase of the molar extinction coefficient from 94 000 to 257 000 M

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Peculiarities of the Energy Transfer of Electronic Excitation in Carbazolyle-Containing Polymers

Ukrainian Journal of Physics ◽

10.15407/ujpe64.5.406 ◽

2019 ◽

Vol 64 (5) ◽

pp. 406

Author(s):

Yu. A. Skryshevski ◽

A. Yu. Vakhnin

Keyword(s):

Energy Transfer ◽

Quantum Yield ◽

Excitation Energy Transfer ◽

Luminescence Spectra ◽

Acceptor Site ◽

Singlet Exciton ◽

Exciton Localization ◽

Direct Excitation ◽

Sensitized Phosphorescence ◽

The One

Luminescence spectra of poly-N-vinylcarbazole (PVK), poly-N-epoxypropylcarbazole (PEPK), poly-N-vinyl-3-chlorocarbazole (Cl-PVK), and polystyrene (PS) films doped with bis[2-(2′-benzothienyl)-pyridinato-N,C3′](acetylacetonate) iridium [Btp2Ir(acac)] have been studied. The indicated carbazole-containing polymers are promising for the application in electroluminescence devices. The quantum yield of sensitized phosphorescence by Btp2Ir(acac) molecules in carbazole-containing polymer matrices is found to be lower than at their direct excitation in the PS matrix. The additional doping of the PVK-based composite with benzophenone, which transforms some of singlet excitons into triplet ones, diminishes the intensity of the sensitized phosphorescence of Btp2Ir(acac) molecules, which testifies that the efficiency of energy transfer via singlet excitons is higher than via triplet ones. The results obtained can be explained by a competition between the process of energy transfer onto the acceptor site, on the one hand, and the processes of exciton localization at the tail energy states and the trapping of triplet excitons by the products of polymer oxidation, on the other hand. The quantum yield of sensitized phosphorescence by Btp2Ir(acac) molecules in the PVK matrix is found to be almost 1.5 times lower than in the PEPK one. A conclusion is drawn that, in the PVKmatrix, the process of singlet exciton autolocalization at excimer-forming centers followed by the creation of sandwich-like excimers competes with the process of excitation energy transfer onto the acceptor.

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Synthesis, electrochemistry, spectroscopy and photophysical properties of a series of meso-phenylpyridylporphyrins with one to four pyridyl rings coordinated to [Ru(bipy)2Cl]+ groups

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424602000063 ◽

2002 ◽

Vol 06 (01) ◽

pp. 33-42 ◽

Cited By ~ 34

Author(s):

Fábio M. Engelmann ◽

Pellegrino Losco ◽

Herbert Winnischofer ◽

Koiti Araki ◽

Henrique E. Toma

Keyword(s):

Energy Transfer ◽

Quantum Yield ◽

Electrochemical Behavior ◽

Fluorescence Quantum Yield ◽

Photophysical Properties ◽

Intramolecular Energy Transfer ◽

Porphyrin Ring ◽

Transfer Processes ◽

Redox Pair ◽

Mlct State

A series of meso-phenylpyridylporphyrins and their respective supermolecular species obtained by the coordination of [ Ru ( bipy )2 Cl ]+ groups to the pyridyl substituents was synthesized and characterized. Their spectroscopic and electrochemical behavior were similar to that observed for the meso-tetra(4-pyridyl)porphyrin derivative, but the redox potential of the Ru (III/II) redox pair was about 70 mV more negative. The porphyrin centered fluorescence quantum yield exhibited a linear decrease as a function of the number of pyridyl substituents on the porphyrin ring. Efficient intramolecular energy transfer processes from the 3 MLCT state of the ruthenium complexes to the porphyrin center were observed at 77K in ethanol glass.

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