Application of time-resolved linear dichroism spectroscopy: Intensity borrowing in charge transfer complex absorption spectra

2003 ◽  
Vol 81 (6) ◽  
pp. 567-574
Author(s):  
Dustin Levy ◽  
Bradley R Arnold
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Complex ◽  
Chlorinated Solvents ◽  
Linear Dichroism ◽  
Charge Transfer Transition ◽  
Time Resolved ◽  
Transition Energies ◽  
Charge Transfer Transitions ◽  
Donor Acceptor ◽  
Influence Of Solvent

Time-resolved linear dichroism spectroscopy has been used to study the influence of solvent on the charge transfer complex formed between hexamethylbenzene and 1,2,4,5-tetracyanobenzene. It was shown that cyano-substituted solvents induce a 1500 cm–1 increase in the charge transfer transition energies relative to those observed in chlorinated solvents. Furthermore, the angle between the charge transfer absorption transition moments and the photochemically produced radical anion absorption transition moment, after relaxation, has been measured for this complex in several solvents. A simple model was used to correlate the angles measured using time-resolved linear dichroism spectroscopy with the extent of localized excitation mixed into the charge transfer transitions. These measurements reveal that different charge transfer transitions borrow intensity from the localized excitation to different extents. By using different excitation wavelengths, the partitioning of the borrowed intensity among the charge transfer transitions of this complex could be evaluated for the first time.Key words: 1,2,4,5-tetracyanobenzene, hexamethylbenzene, donor–acceptor complex, photoinduced electron transfer, photoselection.

Analysis of charge transfer transitions in stacked π-electron donor–acceptor complexes

2018 ◽  
Vol 20 (42) ◽  
pp. 26957-26967 ◽  
Author(s):  
Zhong-hua Cui ◽  
Adélia J. A. Aquino ◽  
Andrew C.-H. Sue ◽  
Hans Lischka
Keyword(s):  
Charge Transfer ◽  
Electron Donor ◽  
Molecular Orbitals ◽  
Charge Transfer Transition ◽  
Charge Transfer Transitions ◽  
Donor Acceptor

Molecular orbitals involved in the charge-transfer transition from 1,5-diaminonaphthalene to pyromellitic diimide.

Light stimulated donor-acceptor forms charge transfer complex in chlorinated solvents

2021 ◽  
Vol 133 (3) ◽  
Author(s):  
Madarapu Naresh ◽  
KS Srivishnu ◽  
Yelukala Rama Krishna ◽  
Madoori Mrinalini ◽  
Seelam Prasanthkumar
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Complex ◽  
Chlorinated Solvents ◽  
Donor Acceptor

Homeotropic alignment through charge-transfer-induced columnar mesophase formation in an unsymmetrically substituted triphenylene derivative

2010 ◽  
Vol 82 (11) ◽  
pp. 1993-2003 ◽  
Author(s):  
Juanjuan Li ◽  
Zhiqun He ◽  
Huan Zhao ◽  
Hemant Gopee ◽  
Xiangfei Kong ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Complex ◽  
X Ray Diffraction ◽  
Hexagonal Symmetry ◽  
X Ray ◽  
Mesophase Formation ◽  
Homeotropic Orientation ◽  
Donor Acceptor ◽  
Homeotropic Alignment ◽  
Spectroscopy Optical

An unsymmetrically substituted triphenylene, with two adjacent chloroethoxyethyl lateral flexible chains, was synthesized and characterized. Although this compound showed no mesomorphic behavior, it formed a donor–acceptor charge-transfer complex with 2,4,7-trinitrofluorenone (TNF). The resulting 1:1 complex has been investigated using UV–vis and IR spectroscopy, optical microscopy, thermal analysis, and X-ray diffraction. A columnar mesophase with hexagonal symmetry was found. More interestingly, this charge-transfer complex can be easily aligned on a glass surface in a homeotropic orientation, which is stable at room temperature (RT) and over a wide temperature range.

scholarly journals Optical anisotropy and charge-transfer transition energies in BiFeO3from 1.0 to 5.5 eV

2011 ◽  
Vol 83 (10) ◽  
Author(s):  
S. G. Choi ◽  
H. T. Yi ◽  
S.-W. Cheong ◽  
J. N. Hilfiker ◽  
R. France ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Optical Anisotropy ◽  
Charge Transfer Transition ◽  
Transition Energies

scholarly journals Long-lived and disorder-free charge transfer states enable endothermic charge separation in efficient non-fullerene organic solar cells

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Ture F. Hinrichsen ◽  
Christopher C. S. Chan ◽  
Chao Ma ◽  
David Paleček ◽  
Alexander Gillett ◽  
...  
Keyword(s):  
Solar Cells ◽  
Charge Transfer ◽  
Organic Solar Cells ◽  
Charge Separation ◽  
Free Charge ◽  
Charge Generation ◽  
Time Resolved ◽  
Thermodynamic Conditions ◽  
Donor Acceptor ◽  
Interfacial Charge

Abstract Organic solar cells based on non-fullerene acceptors can show high charge generation yields despite near-zero donor–acceptor energy offsets to drive charge separation and overcome the mutual Coulomb attraction between electron and hole. Here, we use time-resolved optical spectroscopy to show that free charges in these systems are generated by thermally activated dissociation of interfacial charge-transfer states that occurs over hundreds of picoseconds at room temperature, three orders of magnitude slower than comparable fullerene-based systems. Upon free electron–hole encounters at later times, both charge-transfer states and emissive excitons are regenerated, thus setting up an equilibrium between excitons, charge-transfer states and free charges. Our results suggest that the formation of long-lived and disorder-free charge-transfer states in these systems enables them to operate closely to quasi-thermodynamic conditions with no requirement for energy offsets to drive interfacial charge separation and achieve suppressed non-radiative recombination.

scholarly journals Fermi level pinned molecular donor/acceptor junctions: reduction of induced carrier density by interfacial charge transfer complexes

2020 ◽  
Vol 8 (43) ◽  
pp. 15199-15207
Author(s):  
Paul Beyer ◽  
Eduard Meister ◽  
Timo Florian ◽  
Alexander Generalov ◽  
Wolfgang Brütting ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Fermi Level ◽  
Carrier Density ◽  
Charge Transfer Complex ◽  
Charge Transfer Complexes ◽  
Interfacial Charge Transfer ◽  
Fermi Level Pinning ◽  
Donor Acceptor ◽  
Interfacial Charge

Charge transfer complex (CPX) formation at a donor–acceptor interface reduces the amount of Fermi-level pinning induced interfacial charge transfer.

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