scholarly journals Reversible Energy Transfer and Fluorescence Decay in Solid Solutions

1988 ◽  
Vol 43 (7) ◽  
pp. 627-632 ◽  
Author(s):  
R. Twardowski ◽  
J. Kuśba
Keyword(s):  
Energy Transfer ◽  
Laplace Transform ◽  
Solid Solutions ◽  
Random Distribution ◽  
Excitation Energy Transfer ◽  
Dipole Interaction ◽  
Fluorescence Decay ◽  
Decay Function ◽  
The Laplace Transform ◽  
Hopping Model

Abstract The article deals with the influence of reversible excitation energy transfer on the fluorescence decay in systems with random distribution of molecules. On the basis of a hopping model, we have obtained an expression for the Laplace transform of the decay function and an expression for the average decay time. The case of dipole-dipole interaction is discussed in detail.

A THEORETICAL INTERPRETATION FOR THE EXCITATION ENERGY TRANSFER BETWEEN IDENTICAL MOLECULES IN LIQUID AND SOLID SOLUTION OF HIGH CONCENTRATION

1996 ◽  
Vol 10 (08) ◽  
pp. 347-352
Author(s):  
A.L. PHILIPPETIS
Keyword(s):  
Solid Solution ◽  
Energy Transfer ◽  
Excitation Energy ◽  
Solid Solutions ◽  
Excitation Energy Transfer ◽  
Experimental Results ◽  
Theoretical Interpretation ◽  
Coupling Constant ◽  
High Concentration ◽  
Migration Of Energy

In this work we refer to some experimental results related. as we believe, with excitation energy transfer between molecules of the same kind in liquid and solid solutions of high concentration. We try to explain these results by a theoretical interpretation based on the assumption that the “migration of energy” depends on the distance between the molecules, the orientation of these molecules and on a coupling constant related with the type of these molecules.

Prediction of the Influence of Concentration on the Photoluminescence Decay Time of Solutions

1980 ◽  
Vol 35 (3) ◽  
pp. 345-349 ◽  
Author(s):  
R. Twardowski ◽  
C. Bojarski
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
Decay Time ◽  
Excitation Energy Transfer ◽  
Fluorescence Decay ◽  
Concentration Quenching ◽  
Photoluminescence Decay ◽  
Donor And Acceptor ◽  
Fluorescence Decay Time ◽  
Acceptor Molecules

Abstract A formula for the donor photoluminescence decay time in its dependence on the concentrations of donor D and acceptor A has been derived from equations for the non-radiative excitation energy transfer between randomly distributed donor and acceptor molecules within a nonactive medium. In the limit [D]/[A] → 0 the formula becomes identical with that of Galanin [7], while in the absence of concentration quenching the fluorescence decay time does not depend on the concentrations.

Esm Method and Laplace Transform of Klafter-Bluken Equation for Det Analysis in Polyker Blend Like Naterials.

1992 ◽  
Vol 290 ◽  
Author(s):  
önder Pekcan
Keyword(s):  
Energy Transfer ◽  
Laplace Transform ◽  
Polymer Film ◽  
Vinyl Acetate ◽  
Polymer Films ◽  
Fluorescence Decay ◽  
Lifetime Distribution ◽  
Series Method ◽  
Exponential Series ◽  
Direct Energy

AbstractFluorescence decay curves from particles composed of poly(vinyl acetate) (PVAc) and naphthalene (N) labelled poly (2-ethylhexyl methacrylate) (PEHMA) were analyzed for Direct Energy Transfer (DET) from N to anthracene by the exponential series method(ESM). An averaged apparent dimension of d=2.0 were observed. The Laplace transformed Klafter-Blumen(KB) equation for the lifetime distribution was used to interpret these dimensions. Additional fluorescence experiments were carried out on Polymer films composed of the same material above. Exposure of the films to a pentane solution of 9-anthrylmethyl pivalete (AMP) transferred the AMP molecules exclusively to the PEHMA phase of the material. ESM analysis together with transformed KB equation showed that PEHMA thread has a unique dimension of 1.3 in PVAc matrix of this polymer film.

CONTROL OF THE ENERGY TRANSFER WITH THE OPTICAL MICROCAVITY

2001 ◽  
Vol 15 (28n30) ◽  
pp. 3704-3708 ◽  
Author(s):  
M. HOPMEIER ◽  
W. GUSS ◽  
M. DEUSSEN ◽  
E. O. GÖBEL ◽  
R. F. MAHRT
Keyword(s):  
Energy Transfer ◽  
Excitation Energy Transfer ◽  
Interaction Strength ◽  
Dipole Interaction ◽  
Resonant Mode ◽  
Phenylene Vinylene ◽  
Spectral Position ◽  
Optical Microcavity ◽  
Fabry Perot ◽  
Cavity Resonances

We present the first experimental observation that dipole-dipole interaction can be strongly enhanced by placing the system in a microcavity. We have studied the excitation energy transfer in poly(phenyl-p-phenylene vinylene) (PPPV) doped with DCM molecules, placed within a Fabry-Perot resonator. As the spectral position of the cavity resonant mode in tuned across the DCM absorption profile, the transfer efficiency from PPPV to DCM changes dramatically as revealed by photoluminescence (PL) spectra. This behavior is clear evidence for the increase of the dipole-dipole interaction strength at the cavity resonances mediated by propagating modes emitted from the excited dipoles.

Host-Guest Energy Transfer Via Dipole-Dipole Interaction in Doped Fluorene Crystals

1981 ◽  
Vol 36 (7) ◽  
pp. 697-704 ◽  
Author(s):  
H. Port ◽  
H. Schneckenburger ◽  
H. C. Wolf
Keyword(s):  
Energy Transfer ◽  
Transfer Rate ◽  
Optical Transition ◽  
Dipole Moments ◽  
Dipole Interaction ◽  
Fluorescence Decay ◽  
Oscillator Strengths ◽  
Transition Dipole ◽  
Guest Molecules ◽  
Fluorescence Measurements

Abstract Fluorene mixed crystals have been investigated by sensitized fluorescence measurements in order to prove the importance of dipole-dipole interactions for singlet energy transfer. Fluorene: dibenzofuran (F:DBF) and fluorene:benz[f]indan (F:BI) are used. In these systems the optical transition dipole moments of host and guest molecules are perpendicular and parallel to one another, respectively. For these systems the host-guest energy transfer rate has been determined as a function of the guest concentration from the quantum ratio of guest and host emission (F:BI) and from fluorescence decay time measurements (F:DBF). The latter verified the particularly low transfer rate in F : DBF found in previous steady state investigations. The measured transfer rates at 1.3 K could be explained quantitatively taking into account the relative orientations of the host and guest transition dipoles and the oscillator strengths of the optical transitions. An increase of the transfer rate with increasing temperature between 1.3 K and 100 K in the system F: BI could be related to a change from energy transfer within perturbed states to excitonic band states of the fluorene crystal.

scholarly journals Thermally induced hopping model for long-range triplet excitation energy transfer in DNA

2018 ◽  
Vol 20 (7) ◽  
pp. 4997-5000 ◽  
Author(s):  
Lluís Blancafort ◽  
Alexander A. Voityuk
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
Long Range ◽  
Excitation Energy Transfer ◽  
Thermally Induced ◽  
Triplet Excitation ◽  
Distance Dependence ◽  
Hopping Model

Long-range triplet excitation energy transfer in DNA occurs through hops between T bases, providing it with a shallow distance dependence. Hops over two thymines on the same strand are preferred.

scholarly journals Comparisons of the Efficiency of Excitation Energy Transfer by Singlet and Triplet Excitons in Carbazolyl-Containing Polymers

2018 ◽  
Vol 63 (1) ◽  
pp. 25 ◽  
Author(s):  
Yu. A. Skryshevskii ◽  
O. Yu. Vakhnin
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
Composite Films ◽  
Excitation Energy Transfer ◽  
Dipole Interaction ◽  
Oxidation Products ◽  
Luminescence Spectra ◽  
Direct Excitation ◽  
Additional Doping ◽  
Triplet Excitons

Luminescence spectra of poly-N-epoxypropylecarbazole (PEPC), poly-N-epoxypropyle-3,6- dichlorocarbazole (DClPEPC), and poly-N-epoxypropyle-3,6-dibromocarbazole (DBrPEPC) films, both pure and with the bis[2-(2′ -benzothienyl)-pyridinato-N,C3′ ](acetylacetonate) iridium (Btp2Ir(acac)) admixture, polystyrene (PS) films with the Btp2Ir(acac) admixture, and composite films of PEPC with the benzophenone and Btp2Ir(acac) admixtures have been studied. Those polymers are promising for their application in optoelectronic devices. It is found that, in the case of PEPC matrix, the excitation energy is transferred both via singlet excitons (through migration and long-range dipole-dipole interaction) and triplet ones (due to the migration and short-range electron exchange interaction). At the same time, in the films based on phosphorescent DBrPEPC, the energy transfer is only provided by triplet excitons. It is found that the quantum yield of the sensitized phosphorescence for Btp2Ir(acac) molecules in the carbazolyl-containing polymer matrix is lower than that under their direct excitation in the PS matrix. For the PEPC-based composite, this parameter is found to be three and five times higher than that for the DClPEPC and DBrPEPC matrices, respectively. The additional doping of the PEPC-based composite with benzophenone gave rise to the transformation of some singlet excitons into triplet ones and, as a result, to a reduction of the sensitized Btp2Ir(acac) phosphorescence intensity. A conclusion is drawn that, during the migration, some of both singlet and triplet excitons became localized in the tail energy states, and a certain fraction of triplet excitons is trapped by polymer oxidation products.

Effect of Acceptor Concentration upon Donor Fluorescence Decay and Quantum Yield

1980 ◽  
Vol 35 (10) ◽  
pp. 1030-1035
Author(s):  
C. Bojarski ◽  
E. Grabowska
Keyword(s):  
Energy Transfer ◽  
Rhodamine 6G ◽  
Excitation Energy Transfer ◽  
Fluorescence Decay ◽  
Experimental Results ◽  
Quantum Yields ◽  
Acceptor Concentration ◽  
Decay Times ◽  
Fluorescence Decay Times ◽  
Good Agreement

Abstract The fluorescence decay times (τ/τ0) and quantum yields (η/η0) of rhodamine 6G (donor) in their dependence on the concentration of malachite green (acceptor) in ethanol were measured for the donor to acceptor concentration ratios γᴅ/γᴀ 3.48 and 0.35. At fixed γᴀ, the values of τ/τ0 and η/η0 are markedly lower for the systems with higher γᴅ/γᴀ. The experimental results are compared with the theory of a multistep excitation energy transfer from donor to acceptor. Good agreement between theory and experiment was found for the critical distances ROD = 60.7 Å and ROA = 53.8 Å calculated from spectroscopic data. In the case of γᴅ/γᴀ = 0.35, the experimental results can also be properly described using the Förster-Galanin theory, whereas for the system with γᴅ/γᴀ - 3.48 the multistep energy transfer plays a significant role.

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