Dipole-Dipole Transport of Excitation in Liquid Solutions: Influence of Multi-Stage Energy Transfer on Donor Photoluminescence Yield

1989 ◽  
Vol 44 (9) ◽  
pp. 821-824 ◽  
Author(s):  
J. Kuśba
Keyword(s):  
Energy Transfer ◽  
Diffusion Coefficients ◽  
Size Effects ◽  
Molecular Size ◽  
Quantum Yields ◽  
Transfer Rates ◽  
Multi Stage ◽  
Donor And Acceptor ◽  
Liquid Solutions ◽  
Dipole Energy

Abstract On the basis of expressions obtained earlier, numerical calculations of relative donor quantum yields in the presence of multi-stage dipole-dipole energy transfer and material diffusion are carried out. Transfer rates of the second order obtained from the numerical solution of the diffusion equation with reflecting boundary conditions are used in the calculations. The results reflect the influence of donor and acceptor concentration, magnitude of diffusion coefficients and molecular size effects.

Un exemple d'isomérisation radicalaire en chaînes: la photoinduction de l'isomérisation cis–trans de la pentène-3 one-2

1977 ◽  
Vol 55 (22) ◽  
pp. 3915-3926 ◽  
Author(s):  
Armel Rioual ◽  
André Deflandre ◽  
Jacques Lemaire
Keyword(s):  
Energy Transfer ◽  
Quantum Yields ◽  
Unsaturated Ketone ◽  
Chain Process ◽  
Triplet Energy ◽  
Low Concentrations ◽  
Energy Transfers ◽  
Donor And Acceptor ◽  
A Chain ◽  
Triplet Energy Transfer

Mechanisms of the photosensitized cis–trans photoisomerization of 3-penten-2-one which do not imply only classical triplet–triplet energy transfer are proposed; they are based upon measurements of the variations of initial quantum yields of isomerization with the initial donor and acceptor concentrations, the wavelength of excitation, and the nature of the donor and of the solvent. Carbonyl donors (acetophenone, benzophenone, acetone) induce a radical isomerization by a chain process in reducing solvents; the example of acetophenone is specially interesting. In solvents in which the donor is not photoreduced (as benzene or CCl4) classical triplet–triplet energy transfers occur. Sensitization with aromatic donors (benzene, mesitylene) proceeds through triplet–triplet energy transfer at low concentrations of the acceptor. At higher concentrations of acceptor, an exciplex is formed between the ketone and the aromatic in its singlet excited state; this exciplex is deactivated by dissociation and by causing the isomerization of the α,β-unsaturated ketone.

DENSITY FUNCTIONAL THEORY STUDY OF THE ENERGY TRANSFER RATES, MOLECULAR SIZE, AND ATOMIZATION ENERGIES OF SOME SECONDARY EXPLOSIVE MOLECULES

2008 ◽  
Vol 07 (01) ◽  
pp. 81-90
Author(s):  
SU-HONG GE ◽  
GUANG-XING DONG ◽  
XIN-LU CHENG ◽  
GUI-HUA SUN
Keyword(s):  
Density Functional Theory ◽  
Energy Transfer ◽  
Normal Mode ◽  
Transfer Rate ◽  
Density Functional ◽  
Molecular Size ◽  
Atomization Energy ◽  
Energy Transfer Rate ◽  
Functional Theory ◽  
Transfer Rates

In this paper, we suggested a theoretical relationship between the property of molecular atomization energy and energy transfer rate in explosive detonation. According to the theory of Dlott and Fayer (J Chem Phys92(6):3798, 1990) some explosives are stable molecules with large energy barriers to chemical reaction in shock or impact initiation, so, a sizable amount of phonon energy must be converted to the molecular internal higher vibrations by multiphonon up pumping. To investigate the relationship between atomization energies and energy transfer rate, the number of doorway modes of explosives is estimated by their theory in which the rate is proportional to the number of normal mode vibrations. We evaluated frequencies of normal mode vibrations of TNB, TNAP, TNA, DATB, TATB, 2,4,6-trinitro-benzylalcohol ( C 7 H 5 N 3 O 7), and TNR by means of density functional theory (DFT) at the B3P86/6-31G(d, p) level. It is found that the number of doorway modes shows a linearly correlation to the atomization energies also calculated by means of DFT at the B3P86/6-31G(d, p) level. Besides, we studied the relation between the number of atoms and atomization energies for these molecules, and confirmed that for those secondary explosives molecules with similar molecular structure and similar molecular weight, the correlation between the atomization energy and the number of doorway modes is higher. This relationship is beneficial to the understanding of the property of explosive in detonation.

Very fast singlet and triplet energy transfers in a tri-chromophoric porphyrin dyad aided by the truxene platform

2015 ◽  
Vol 19 (01-03) ◽  
pp. 427-441 ◽  
Author(s):  
Adam Langlois ◽  
Hai-Jun Xu ◽  
Paul-Ludovic Karsenti ◽  
Claude P. Gros ◽  
Pierre D. Harvey
Keyword(s):  
Energy Transfer ◽  
Electron Exchange ◽  
Triplet Energy ◽  
Transfer Rates ◽  
Transfer Processes ◽  
Energy Transfers ◽  
Donor And Acceptor ◽  
Double Electron ◽  
Fast Rates

A trichromophoric dyad composed of an octa-β-alkyl-palladium(II)porphyrin (donor) and two tri-meso-aryl-zinc(II)porphyrins (acceptors) held by a truxene spacer exhibits very fast rates for triplet energy transfers at 77 (kET(T1) = 1.63 × 108 s-1) and 298 K (kET(T1) = 3.44 × 108 s-1), whereas the corresponding singlet energy transfer rates, kET(S1) = 3.9 × 1010 s-1 (77 K) and kET(S1) = 6.0 × 1010 s-1 (298 K), are also considered fast. The interpretation for these results is that the energy transfer processes proceed via a through bond Dexter mechanism (i.e. double electron exchange) supported by comparison with literature data and evidence for a moderate MO coupling between the donor and acceptor chromophores in the frontier MOs.

Origin of the Red Sites and Energy Transfer Rates in Single MEH-PPV Chains at Low Temperature

ChemPhysChem ◽  
2011 ◽  
Vol 12 (8) ◽  
pp. 1499-1508 ◽  
Author(s):  
Florian A. Feist ◽  
Martin F. Zickler ◽  
Thomas Basché
Keyword(s):  
Energy Transfer ◽  
Low Temperature ◽  
Transfer Rates

scholarly journals High-performance quasi-2D perovskite light-emitting diodes: from materials to devices

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Li Zhang ◽  
Changjiu Sun ◽  
Tingwei He ◽  
Yuanzhi Jiang ◽  
Junli Wei ◽  
...  
Keyword(s):  
Energy Transfer ◽  
High Performance ◽  
Light Emitting Diodes ◽  
Structural Characteristics ◽  
Quantum Yields ◽  
Research Directions ◽  
Light Emitting ◽  
Perovskite Materials ◽  
Quantum Confinement Effects ◽  
Semiconducting Properties

AbstractQuasi-two-dimensional (quasi-2D) perovskites have attracted extraordinary attention due to their superior semiconducting properties and have emerged as one of the most promising materials for next-generation light-emitting diodes (LEDs). The outstanding optical properties originate from their structural characteristics. In particular, the inherent quantum-well structure endows them with a large exciton binding energy due to the strong dielectric- and quantum-confinement effects; the corresponding energy transfer among different n-value species thus results in high photoluminescence quantum yields (PLQYs), particularly at low excitation intensities. The review herein presents an overview of the inherent properties of quasi-2D perovskite materials, the corresponding energy transfer and spectral tunability methodologies for thin films, as well as their application in high-performance LEDs. We then summarize the challenges and potential research directions towards developing high-performance and stable quasi-2D PeLEDs. The review thus provides a systematic and timely summary for the community to deepen the understanding of quasi-2D perovskite materials and resulting LED devices.

B800–B850 coherence correlates with energy transfer rates in the LH2 complex of photosynthetic purple bacteria

2015 ◽  
Vol 17 (46) ◽  
pp. 30805-30816 ◽  
Author(s):  
Cathal Smyth ◽  
Daniel G. Oblinsky ◽  
Gregory D. Scholes
Keyword(s):  
Energy Transfer ◽  
Quantum Information ◽  
Information Science ◽  
Light Harvesting ◽  
Purple Bacteria ◽  
Quantum Information Science ◽  
Light Harvesting Complex ◽  
Transfer Rates ◽  
Photosynthetic Purple Bacteria

Delocalization of a model light-harvesting complex is investigated using multipartite measures inspired by quantum information science.

Control of Förster energy transfer in the vicinity of metallic surfaces and hyperbolic metamaterials

2015 ◽  
Vol 178 ◽  
pp. 395-412 ◽  
Author(s):  
T. U. Tumkur ◽  
J. K. Kitur ◽  
C. E. Bonner ◽  
A. N. Poddubny ◽  
E. E. Narimanov ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Spontaneous Emission ◽  
Practical Importance ◽  
Index Of Refraction ◽  
Metallic Surfaces ◽  
Dielectric Media ◽  
Plasmonic Structures ◽  
Donor And Acceptor ◽  
Förster Energy Transfer ◽  
Photonic States

Optical cavities, plasmonic structures, photonic band crystals and interfaces, as well as, generally speaking, any photonic media with homogeneous or spatially inhomogeneous dielectric permittivity (including metamaterials) have local densities of photonic states, which are different from that in vacuum. These modified density of states environments are known to control both the rate and the angular distribution of spontaneous emission. In the present study, we question whether the proximity to metallic and metamaterial surfaces can affect other physical phenomena of fundamental and practical importance. We show that the same substrates and the same nonlocal dielectric environments that boost spontaneous emission, also inhibit Förster energy transfer between donor and acceptor molecules doped into a thin polymeric film. This finding correlates with the fact that in dielectric media, the rate of spontaneous emission is proportional to the index of refractionn, while the rate of the donor–acceptor energy transfer (in solid solutions with a random distribution of acceptors) is proportional ton−1.5. This heuristic correspondence suggests that other classical and quantum phenomena, which in regular dielectric media depend onn, can also be controlled with custom-tailored metamaterials, plasmonic structures, and cavities.

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