Premium
Photophysics and Inverted Solvatochromism of 7,7,8,8‐Tetracyanoquinodimethane (TCNQ)
Author(s) -
Tamaya Honami,
Torii Yuto,
Ishikawa Takumi,
Nakano Hideyuki,
Iimori Toshifumi
Publication year - 2019
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201900681
Subject(s) - solvatochromism , chemistry , oscillator strength , excited state , raman spectroscopy , tetracyanoquinodimethane , quantum yield , absorption (acoustics) , transition dipole moment , absorption spectroscopy , photochemistry , analytical chemistry (journal) , fluorescence , dipole , solvent , materials science , spectral line , atomic physics , molecule , organic chemistry , optics , physics , astronomy , composite material
We report absorption, fluorescence, and Raman spectroscopy of 7,7,8,8‐tetracyanoquinodimethane (TCNQ) in a variety of solvents. The fluorescence quantum yields (QYs) of linear alkane solutions are similar to one another, but QY is shown to acutely decrease in other solvents with increasing polarities. The slope of the solvatochromic plot of absorption maxima is inverted from negative to positive with an increase in solvent polarity. A significant change in the frequency of carbon‐carbon double bond stretching modes is not observed in Raman spectra of TCNQ in different solvents. The molar absorption coefficient is determined to calculate the oscillator strength of the absorption band. The radiative decay rate constant calculated from the oscillator strength is approximately ten times larger than that elucidated from the fluorescence lifetime and QY. These spectroscopic parameters reveal that the relaxation occurs from a Franck‐Condon excited state to a distinct fluorescence emissive state with a smaller transition dipole moment.