scholarly journals One- and two-photon solvatochromism of the fluorescent dye Nile Red and its CF3, F and Br-substituted analogues

2020 ◽  
Vol 19 (10) ◽  
pp. 1382-1391 ◽  
Author(s):  
Mick Hornum ◽  
Peter Reinholdt ◽  
Jan K. Zaręba ◽  
Brian B. Jensen ◽  
Daniel Wüstner ◽  
...  
Keyword(s):  
Cross Section ◽  
Nile Red ◽  
Solvent Polarity ◽  
Fluorescent Dye ◽  
Two Photon ◽  
Photon Cross Section ◽  
Electron Withdrawing Substituents

Nile Red is a valuable fluorescent dye for studying lipophilic environments. This study presents how solvent polarity and decoration with simple electron-withdrawing substituents influence its absorption, fluorescence and two-photon cross-section.

scholarly journals Ultrafast processes triggered by one- and two-photon excitation of a photochromic and luminescent hydrazone

2019 ◽  
Vol 15 ◽  
pp. 2438-2446 ◽  
Author(s):  
Alessandro Iagatti ◽  
Baihao Shao ◽  
Alberto Credi ◽  
Barbara Ventura ◽  
Ivan Aprahamian ◽  
...  
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Transient Absorption ◽  
Solvent Polarity ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Time Resolved ◽  
Two Photon Absorption ◽  
Two Photon

In this work we apply a combination of steady state and time resolved luminescence and absorption spectroscopies to investigate the excited-state dynamics of a recently developed molecular photoswitch, belonging to the hydrazone family. The outstanding properties of this molecule, involving fluorescence toggling, bistability, high isomerization quantum yield and non-negligible two-photon absorption cross section, make it very promising for numerous applications. Here we show that the light induced Z/E isomerization occurs on a fast <1 ps timescale in both toluene and acetonitrile, while the excited state lifetime of the Z-form depends on solvent polarity, suggesting a partial charge transfer nature of its low lying excited state. Time-resolved luminescence measurements evidence the presence of a main emission component in the 500–520 nm spectral range, attributed to the Z-isomer, and a very short living blue-shifted emission, attributed to the E-isomer. Finally, transient absorption measurements performed upon far-red excitation are employed as an alternative method to determine the two-photon absorption cross-section of the molecule.

Water-Soluble Paracyclophane Fluorophores with Large Two-Photon Action Cross Sections

2005 ◽  
Vol 871 ◽  
Author(s):  
Han Young Woo ◽  
Dmitry Korystov ◽  
Alexander Mikhailovsky ◽  
Guillermo C. Bazan
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Solvent Polarity ◽  
Water Soluble ◽  
Photon Absorption ◽  
Significant Drop ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Donor Ability ◽  
Fine Tune

AbstractA series of tetradonor substituted [2.2]paracyclophane-based two-photon absorption (TPA) fluorophores were designed, synthesized and characterized. Different substituents were chosen to modulate the conjugation and the donor strength and to allow the molecules to be neutral (N series, organic-soluble) or charged (C series, water-soluble). The overall set of compounds series allows us to examine the correlation among the solvent polarity, donor ability of the substituents, and TPA action cross section (ηδd, where δ is the TPA cross section and η is the quantum yield). In water, a significant drop of both δ and η is observed, approximately one-third relative to those in toluene. Weaker donors and/or weaker acceptors with enhanced conjugation are a better choice due to a minimized quenching related to strong charge transfer (CT) upon excitation. One thus needs to fine-tune the magnitude of CT and find an optimal balance among CT,δ and η.

Absolute two-photon cross section of Rb measured by differential absorption

1993 ◽  
Vol 18 (20) ◽  
pp. 1754 ◽  
Author(s):  
C. L. A. Collins ◽  
K. D. Bonin ◽  
M. A. Kadar-Kallen
Keyword(s):  
Cross Section ◽  
Differential Absorption ◽  
Two Photon ◽  
Photon Cross Section
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