scholarly journals Probing Local Environments by Time-Resolved Stimulated Emission Spectroscopy

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Ana Rei ◽  
Graham Hungerford ◽  
Michael Belsley ◽  
M. Isabel C. Ferreira ◽  
Peter Schellenberg
Keyword(s):  
Emission Spectroscopy ◽  
Sol Gel ◽  
Fluorescence Emission ◽  
Local Environment ◽  
Fluorescence Decay ◽  
Stimulated Emission ◽  
Binary Solvents ◽  
Time Resolved ◽  
Local Environments ◽  
Lower Viscosity

Time-resolved stimulated emission spectroscopy was employed to probe the local environment of DASPMI (4-(4-(dimethylamino)styryl)-N-methyl-pyridinium iodide) in binary solvents of different viscosity and in a sol-gel matrix. DASPMI is one of the molecules of choice to probe local environments, and the dependence of its fluorescence emission decay on viscosity has been previously used for this purpose in biological samples, solid matrices as well as in solution. The results presented in this paper show that time-resolved stimulated emission of DASPMI is a suitable means to probe the viscosity of local environments. Having the advantage of a higher time resolution, stimulated emission can provide information that is complementary to that obtained from fluorescence decay measurements, making it feasible to probe systems with lower viscosity.

scholarly journals Fluorescent Silica Hybrid Film-Forming Materials Based on Salicylaldazine

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1255
Author(s):  
Alina Raditoiu ◽  
Valentin Raditoiu ◽  
Florentina Monica Raduly ◽  
Georgiana Cornelia Ispas ◽  
Violeta Purcar ◽  
...  
Keyword(s):  
Photophysical Properties ◽  
Sol Gel ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Hybrid Films ◽  
Fluorescence Emission Spectra ◽  
Network Modifier ◽  
Local Environments ◽  
Film Forming ◽  
Silica Sols

Fluorescent film-forming materials were obtained by embedding salicylaldazine (SAA) in silica hybrids generated by sol–gel processes from different silane precursors in acid catalysis. Tuned local environments for the fluorophore were generated in the hosting network by modifying silica sols with organic groups through the co-condensation of tetraethylortosilicate (TEOS) and different alkoxysilanes hydrolysis products. The photophysical properties of the luminescent hybrid films were studied in direct relationship with structural, textural, and surface properties and based on interactions between SAA species and the silica hosting network. Film-forming materials were studied in order to determine differences in absorption and fluorescence emission due to the environments around the fluorophore. The variations recorded in the fluorescence emission spectra of the hybrid films were related to interactions established between the fluorophore species and their sterically hindered surroundings of the host hybrid silica, where free molecular motions are restricted. The influence of the type and amount of network modifier and of the fluorophore loading on the transparency of the films and fluorescence intensity was also investigated. The study carried out led to the elucidation of the necessary conditions for obtaining luminescent film-forming materials with high luminescence intensity and transparency useful for the design of new light concentrators.

Fluorescence Quenching and Solvation Processes of Fluorenone and 4-hydroxyfluorenone in Binary Solvents

2003 ◽  
Vol 58 (2-3) ◽  
pp. 144-156 ◽  
Author(s):  
M. Jozefowicza ◽  
J. R. Heldt ◽  
J. Karolczak ◽  
J. Heldt
Keyword(s):  
Hydrogen Bond ◽  
Photophysical Properties ◽  
Equilibrium Constants ◽  
Mixed Solvents ◽  
Emission Spectra ◽  
Fluorescence Decay ◽  
Binary Solvents ◽  
Time Resolved ◽  
Decay Times ◽  
Fluorescence Light

Steady state and time-resolved spectroscopic measurements of fluorenone and 4-hydroxyfluorenone dissolved in binary nonpolar, polar and polar protic mixed solvents have been performed at room temperature. The absorption and emission spectra show that, apart from the free molecules, hydrogen bond complexes exist in the ground and excited states in the mixed solvents used. The data obtained were used to determine the stoichiometric equilibrium constants. The fluorescence decay data point that in the binary used solutions the radiation appears from an assembly of luminescence centers emitting fluorescence light of different wavelengths and decay times. Molecules forming simple hydrogen bond complexes (with fluorenone) show different photophysical properties from those where a proton-relay complex (with 4-hydroxyfluorenone) is established.

Time-resolved stimulated emission spectroscopy in the ultrashort domain through pump–probe experiments

2007 ◽  
Vol 254 (4) ◽  
pp. 859-862 ◽  
Author(s):  
S. Orlando ◽  
A. Paladini ◽  
L. Guidoni ◽  
A. Santagata ◽  
G.P. Parisi ◽  
...  
Keyword(s):  
Emission Spectroscopy ◽  
Stimulated Emission ◽  
Time Resolved ◽  
Pump Probe

Time-Resolved Stimulated-Emission Fluorescence Microscope

1996 ◽  
Vol 54 ◽  
pp. 278-279
Author(s):  
P. T. C. So ◽  
C. Y. Dong ◽  
C. Buhler ◽  
E. Gratton
Keyword(s):  
Spatial Resolution ◽  
Focal Point ◽  
Resolution Enhancement ◽  
Fluorescence Emission ◽  
Stimulated Emission ◽  
Time Resolved ◽  
Emission Point ◽  
Point Spread ◽  
Pump And Probe ◽  
Nanosecond Time Resolution

Time-resolved stimulated-emission fluorescence microscopy is a novel technique for obtaining super-diffraction limited spatial resolution and sub-nanosecond time resolution using a multi-photon process. This technique is inspired by traditional asynchronous stimulated-emission pump-probe spectroscopy. Fluorescence sample is first excited by a pump laser pulse, tuned to the molecular absorption band of the molecule. Within the chromophore lifetime, a second probe pulse, tuned to the emission band, stimulates fluorescence emission.The spatial resolution enhancement originates from the bilinear dependence of the stimulated emission efficiency on both the pump and probe beam intensities. At the objective focal point, the stimulated emission point spread function is the product of the point spread functions of the pump and probe beams. This situation is mathematically equivalent to both the confocal and the two-photon methods. 3-D depth discrimination and superior spatial resolution is expected.

scholarly journals Photophysical properties and fluorosolvatochromism of D–π–A thiophene based derivatives

RSC Advances ◽  
2020 ◽  
Vol 10 (71) ◽  
pp. 43459-43471
Author(s):  
Hussain A. Z. Sabek ◽  
Ahmed M. M. Alazaly ◽  
Dina Salah ◽  
Hesham S. Abdel-Samad ◽  
Mohamed A. Ismail ◽  
...  
Keyword(s):  
Photophysical Properties ◽  
Fluorescence Emission ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
Solvation Models

Solvation-dependent photophysical properties of two push–pull thiophene-based compounds with donor–π–acceptor (D–π–A) structures were investigated using absorption, fluorescence emission and time resolved spectroscopy, and supported by different solvation models.

scholarly journals Photophysical Properties of Protoporphyrin IX, Pyropheophorbide-a, and Photofrin® in Different Conditions

2021 ◽  
Vol 14 (2) ◽  
pp. 138
Author(s):  
Bauyrzhan Myrzakhmetov ◽  
Philippe Arnoux ◽  
Serge Mordon ◽  
Samir Acherar ◽  
Irina Tsoy ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Photophysical Properties ◽  
Protoporphyrin Ix ◽  
Fluorescence Emission ◽  
Solvent Polarity ◽  
Visible Absorption ◽  
Light Dosimetry ◽  
Time Resolved ◽  
Pyropheophorbide A ◽  
Influence Of Solvent

Photodynamic therapy (PDT) is an innovative treatment of malignant or diseased tissues. The effectiveness of PDT depends on light dosimetry, oxygen availability, and properties of the photosensitizer (PS). Depending on the medium, photophysical properties of the PS can change leading to increase or decrease in fluorescence emission and formation of reactive oxygen species (ROS) especially singlet oxygen (1O2). In this study, the influence of solvent polarity, viscosity, concentration, temperature, and pH medium on the photophysical properties of protoporphyrin IX, pyropheophorbide-a, and Photofrin® were investigated by UV-visible absorption, fluorescence emission, singlet oxygen emission, and time-resolved fluorescence spectroscopies.

scholarly journals Architecture of Polyglutamine-containing Fibrils from Time-resolved Fluorescence Decay

2014 ◽  
Vol 289 (39) ◽  
pp. 26817-26828 ◽  
Author(s):  
Christoph Röthlein ◽  
Markus S. Miettinen ◽  
Tejas Borwankar ◽  
Jörg Bürger ◽  
Thorsten Mielke ◽  
...  
Keyword(s):  
Fluorescence Decay ◽  
Time Resolved Fluorescence ◽  
Time Resolved
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