Evaluating the Effect of Heteroatoms on the Photophysical Properties of Donor–Acceptor Conjugated Polymers Based on 2,6-Di(thiophen-2-yl)benzo[1,2-b:4,5-b′]difuran: Two-Photon Cross-Section and Ultrafast Time-Resolved Spectroscopy

2017 ◽  
Vol 121 (27) ◽  
pp. 14382-14392 ◽  
Author(s):  
Ricardo J. Vázquez ◽  
Hyungjun Kim ◽  
Brandon M. Kobilka ◽  
Benjamin J. Hale ◽  
Malika Jeffries-EL ◽  
...  
Keyword(s):  
Conjugated Polymers ◽  
Cross Section ◽  
Photophysical Properties ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
Two Photon ◽  
Donor Acceptor ◽  
Photon Cross Section

Comparative photophysics of sapphyrin derivatives: effects of confused and fused pyrrole rings

2011 ◽  
Vol 15 (09n10) ◽  
pp. 858-864 ◽  
Author(s):  
Jong Min Lim ◽  
Iti Gupta ◽  
Hiroyuki Furuta ◽  
Dongho Kim
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Photophysical Properties ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Time Resolved ◽  
Nonradiative Decay ◽  
Two Photon Absorption ◽  
Two Photon

We have investigated the photophysical properties of [22] π-conjugated pentapyrrolic systems, sapphyrin, N-confused and N-fused sapphyrins, with a particular focus on the effects of confused and fused pyrrole rings on their electronic structures using steady-state and time-resolved spectroscopic methods, two-photon absorption cross-section (σ(2)) measurements and quantum mechanical calculations. The absorption spectra of N-confused and N-fused sapphyrins exhibit relatively red-shifted features compared to sapphyrin. In parallel with these spectral features, the reduced HOMO–LUMO gaps were observed in going from sapphyrin to N-fused sapphyrin. In the analysis of the anisotropy of the induced current density (AICD), N-confused and N-fused sapphyrins show that extra π-electrons in confused and fused pyrrole rings contribute to the extension of their π-conjugation pathways. Slightly larger twophoton absorption cross-section values of N-confused and N-fused sapphyrins (3250 and 3900 GM) than that of sapphyrin (2900 GM) also reflect an enhanced π-conjugation effect due to bicyclic and endocyclic extensions in π-conjugation pathways, respectively. The excited singlet and triplet state lifetimes of N-confused sapphyrin were determined to be 60 ps and 1 μs, respectively, due to conformational change and acceleration of nonradiative decay processes, being in a sharp contrast with those of sapphyrin (2.4 ns and 13 μs, respectively). In the case of N-fused sapphyrin, very short singlet excited-state lifetime of 5 ps was detected probably due to the excited-state NH-tautomerization process which enhances nonradiative decay processes.

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 Time-resolved Spectroscopy of the violet luminescence of undoped AlN

2005 ◽  
Vol 10 ◽  
Author(s):  
R. Freitag ◽  
K. Thonke ◽  
R. Sauer ◽  
D. G. Ebling ◽  
L. Steinke
Keyword(s):  
Epitaxial Layers ◽  
Yellow Luminescence ◽  
Acceptor Pair ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
Violet Luminescence ◽  
Donor Acceptor ◽  
Violet Band ◽  
Donor Acceptor Pair

We report on the time-resolved luminescence of the defect-related violet band from undoped AlN epitaxial layers grown on sapphire and SiC. For both measurements in photoluminescence and in cathodoluminescence a decay of algebraic nature at long times is observed. This is typical for donor-acceptor pair transitions. We compare the behavior of this band to that of the generically yellow luminescence of GaN.

Synthesis and photophysical properties of extended π conjugated naphthalimides

2017 ◽  
Vol 16 (4) ◽  
pp. 539-546 ◽  
Author(s):  
C. Rémy ◽  
C. Allain ◽  
I. Leray
Keyword(s):  
Charge Transfer ◽  
Dft Calculations ◽  
Photophysical Properties ◽  
Photoinduced Charge Transfer ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
Td Dft ◽  
Photoinduced Charge

A series of π conjugated naphthalimide derivatives were prepared. Compounds display efficient photoinduced charge transfer in solution which was rationalized by time-resolved spectroscopy and modelled by TD-DFT calculations.

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.

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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