Direct Nonradiative Energy Transfer in Polymer Interphases: Fluorescence Decay Functions from Concentration Profiles Generated by Fickian Diffusion

1995 ◽  
Vol 28 (18) ◽  
pp. 6084-6088 ◽  
Author(s):  
J. P. S. Farinha ◽  
J. M. G. Martinho ◽  
A. Yekta ◽  
M. A. Winnik
Keyword(s):  
Energy Transfer ◽  
Fluorescence Decay ◽  
Nonradiative Energy Transfer ◽  
Fickian Diffusion ◽  
Concentration Profiles

Fluorescence energy transfer studies in a cross-linked polyurethane network

1995 ◽  
Vol 73 (11) ◽  
pp. 1823-1830 ◽  
Author(s):  
Jie Yang ◽  
Mitchell A. Winnik
Keyword(s):  
Energy Transfer ◽  
Fluorescence Quenching ◽  
Fluorescence Decay ◽  
Critical Distance ◽  
Nonradiative Energy Transfer ◽  
Fluorescence Energy Transfer ◽  
Distribution Analysis ◽  
Analysis Method ◽  
Acceptor Concentration ◽  
Fluorescence Energy

A series of cross-linked polyurethane samples, labeled with dyes suitable for fluorescence energy transfer experiments, were prepared (donor, phenanthrene; acceptor, anthracene). Fluorescence decay profiles for these samples were measured as a function of acceptor concentration. These decays obey Förster nonradiative energy transfer kinetics, with an energy transfer critical distance (R0) of 26.7 Å. Fluorescence intensities, calculated from the decays by integrating the decay profiles, also fit the Perrin model, with a quenching radius (Rs) of 25.6 Å. The fluorescence decay profiles were further examined with a distribution analysis method, which also revealed uniformly distributed donors and acceptors in the polymer matrices. Keywords: fluorescence quenching, fluorescence decay, phenanthrene, anthracene, polyurethane.

Neodymium-to-erbium nonradiative energy transfer and fast initial fluorescence decay of the ^4F_3/2 state of neodymium in garnet crystals

1997 ◽  
Vol 14 (10) ◽  
pp. 2731 ◽  
Author(s):  
Oracio Barbosa-García ◽  
Ross A. McFarlane ◽  
Milton Birnbaum ◽  
Luis Armando Díaz-Torres
Keyword(s):  
Energy Transfer ◽  
Fluorescence Decay ◽  
Nonradiative Energy Transfer

Recent Applications of Nonradiative Energy Transfer to Polymer Studies

1993 ◽  
Vol 58 (10) ◽  
pp. 2266-2271 ◽  
Author(s):  
Herbert Morawetz
Keyword(s):  
Energy Transfer ◽  
Polymer Chain ◽  
Cluster Formation ◽  
Nonradiative Energy Transfer ◽  
Molecular Cluster ◽  
Fluorescent Labels ◽  
Latex Particles ◽  
Polymer Latex

Recent studies of polymers in solution and in bulk by energy transfer between two fluorescent labels are reviewed. Such studies are concerned with the equilibrium and dynamics of polymer chain expansion, molecular cluster formation in solution, the miscibility of polymers in bulk, and the interdiffusion of polymer latex particles.

Synthesis and Photophysical Properties of a Conformationally Flexible Mixed Porphyrin Star-Pentamer

2009 ◽  
Vol 62 (7) ◽  
pp. 692 ◽  
Author(s):  
Toby D. M. Bell ◽  
Sheshanath V. Bhosale ◽  
Kenneth P. Ghiggino ◽  
Steven J. Langford ◽  
Clint P. Woodward
Keyword(s):  
Energy Transfer ◽  
Photophysical Properties ◽  
Fluorescence Decay ◽  
High Yield ◽  
Free Base ◽  
Time Resolved ◽  
Zinc Porphyrin ◽  
Relative Contribution ◽  
Synthetic Strategy ◽  
Decay Times

The synthesis of a porphyrin star-pentamer bearing a free-base porphyrin core and four zinc(ii) metalloporphyrins, which are tethered by a conformationally flexible linker about the central porphyrin’s antipody, is described. The synthetic strategy is highlighted by the use of olefin cross metathesis to link the five chromophores together in a directed fashion in high yield. Photoexcitation into the Soret absorption band of the zinc porphyrin chromophores at 425 nm leads to a substantial enhancement of central free-base porphyrin fluorescence, indicating energy transfer from the photoexcited zinc porphyrin (outer periphery) to central free-base porphyrin. Time-resolved fluorescence decay profiles required three exponential decay components for satisfactory fitting. These are attributed to emission from the central free-base porphyrin and to two different rates of energy transfer from the zinc porphyrins to the free-base porphyrin. The faster of these decay components equates to an energy-transfer rate constant of 3.7 × 109 s–1 and an efficiency of 83%, whereas the other is essentially unquenched with respect to reported values for zinc porphyrin fluorescence decay times. The relative contribution of these two components to the initial fluorescence decay is ~3:2, similar to the 5:4 ratio of cis and trans geometric isomers present in the pentamer.

Luminescence Linewidth Broadening and Nonradiative Energy Transfer Studies of Solid UO2+2-Datura

1992 ◽  
Vol 46 (9) ◽  
pp. 1376-1381 ◽  
Author(s):  
Huei-Yang D. Ke ◽  
Gary D. Rayson
Keyword(s):  
Energy Transfer ◽  
Emission Spectra ◽  
Blue Shift ◽  
Liquid Nitrogen Temperature ◽  
Peak Position ◽  
Nonradiative Energy Transfer ◽  
Wall Material ◽  
Transfer Model ◽  
Solution Ph ◽  
Linewidth Broadening

The emission spectra and fluorescence decay curves of solid UO2+2- Datura at liquid nitrogen temperature have been measured. The linewidth of the emission peaks of UO2+2 ions in UO2+2- Datura decreases with the UO2+2 concentration. This linewidth broadening phenomenon can be explained by the existence of resonance interactions between adjacent UO2+2- Datura species. The analysis of the emission peak position of the bound ions has been used to provide a measure of the electronic factors contributing to the interaction between the uranyl ion and phosphoryl and dicarboxyl moieties on the cell wall material. An observed blue shift of the uranyl fluorescence spectrum as a function of solution pH has been ascribed to a distortion of the normally linear O-U-O bond. An inter- and intra-molecular nonradiative energy transfer model has been successfully used to interpret the measured lifetime data of UO2+2- Datura.

Sign in / Sign up

Export Citation Format

Share Document