Fluorescence spectroscopic studies on the radical cations of tetrathiafulvalenes

Fluorescence spectroscopic studies have been performed on the radical catio ns of tetrathiafulvalene (TTF), 4,4'-dimethyl-5,5'-diphenyltetrathiafulvale ne (DMDP-TTF), bis-(4,5-dihydronaphtho-[1,2d]-tetrathiafulvalene) (BDHN-TTF ) and bis-(ethylenedithio)-tetrathiafulvalene (BEDT-TTF) in low-temperature organic glasses. For the first time emission and excitation spectra have b een obtained for radical cations of this class of compounds. Only in the ca se of BFDT-TTF.+ fluorescence could not be detected. The luminescence spect ra have been related to the corresponding UV/Vis/NIR absorption spectra and absorption data obtained using the LNDO/S PERTCI method. For DMDP-TTF.+ th e fluorescence lifetime (1.09 ns) has been measured and the fluorescence qu antum yield (5 x 10(-3)) has been estimated. (C) 1999 Elsevier Science B.V. All rights reserved.