Physico-Chemical nanomaterials science
Spectral pecularities of spin-coated thin fims based on merocyanine dyes

Pavlenko O. L.1, Dmytrenko O. P. 1, Gaponov A. M.1, Kulish M. P.1 
Pundyk I.P.1, Kachkovsky O. D.2, Kurdiukov V. V. 3, Lesiuk A.I. 1, P.Kobzar 1
1 Department of physics of functional materials, Physics Faculty, National Taras Shevchenko University of Kyiv, Glushkova prosp., 4, Kyiv-03039, Ukraine. 
E-mail: lesyuk.andrey@gmail.com
2 V.P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry of the National Academy of Sciences of Ukraine, Murmanska st., 1, Kyiv-02094, Ukraine.
3  Institute of Organic Chemistry of the National Academy of Sciences of Ukraine, Murmanska st., 5, Kyiv-02660, Ukraine.

Optical properties of merocyanine dyes films prepared by spin-coating on the glass substrates were studied by absorption spectra and quantum chemical modelling. Absorbance of the films comparing to the spectra in solution undergoes the following changes: absorption maxima shift towards red region and new wide maxima appear; absorption intensity of the main peak decreases. Those take place due to the interaction of the considered molecules due to alternation of atomic charges on the molecular chromophores. Consequently, J- and T-type aggregates are formed, which is confirmed by quantum-chemical calculations. According to the obtained data T-aggregation prevails. The modeling of interaction between the dyes, calculations of equilibrium geometry, charge distribution and electronic states were carried out as well. 
Therefore, merocyanine dyes in films absorb wider spectral region which can be used for harvesting of solar energy in order to transform it into electricity power in solar elements of organic electronics.