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ISSN 2071-0194   Ukr. J. Phys. 2015, Vol. 60, N 7, p.593-600
doi:10.15407/ujpe60.07.0593   Paper

Borysyuk V.І.1, Yashchuk V.M.1, Naumenko A.P.1, Stanova А.V.1, Gerasova V.G.2, Gerasov А.O.3, Kovtun Yu.P.3, Shandura M.P.3, Kachkovsky O.D.3

1 Taras Shevchenko National University of Kyiv, Faculty of Physics
(64/13, Volodymyrs’ka Str., Kyiv 01601, Ukraine)
2 Taras Shevchenko National University of Kyiv, Faculty of Chemistry
(64/13, Volodymyrs’ka Str., Kyiv 01601, Ukraine)
3 Institute of Organic Chemistry, Nat. Acad. of Sci. of Ukraine
(5, Murmans’ka Str., Kyiv 03660, Ukraine)

Influence of Surplus Negative Charge on Absorption and Fluorescence Excitation Spectra of Asymmetric Polymethine Dyes

Section: Optics, Lasers, and Quantum Electronics
Language: English

Abstract: The combined spectral and quantum-chemical investigations of the vinylog series of the asymmetric anionic polymethine dyes, derivatives of aminocoumarin, as well as the related symmetric dyes, are fulfilled. The charge injection to these types of dyes leads to the essential shifts of electronic levels. The calculations show the inverse character of the first two electron transitions in anionic polymethines and relative cationic polymethines. It is established that going to asymmetric dyes leads to a slight decrease of the spectral effect of the chromophore lengthening. The influence of the asymmetry manifests itself in a positive deviation in the absorption spectra and a negative deviation of the second electron transition manifested visually in the anisotropy of the fluorescence excitation spectra of asymmetric dyes. It is found that the lengthening of the chromophore is accompanied by an increase of the deviation of the first electron transition and, in contrast, by a decrease of the deviation of the second transition. The obtained results may be used in the design of molecular systems with prognosed current-voltage characteristics for nanoelectronics.

Key words: anion polymethine dyes, absorption spectra, fluorescence spectra, fluorescence excitation anisotropy spectra, quantum-chemical calculations, current-voltage characteristic.