Research


Projects

P2

Thiophene based Polymers: Correlation of Fluorescence Dynamics and Structure Topography towards Photovoltaics


Topography and electron dynamics of polythiopehene based copolymer, as photovoltaic material, are correlated by means of using atomic force microscopy and time-resolved fluorescence spectroscopy, respectively. The dimethyl ester of 3,3````-bisdecyl [2,2`; 5`,2``; 5``,2```; 5```, 2````; 5````, 2`````] sexithiophene-5,5`````-dicarboxylic acid, with polyethylene oxide, copolymer (ST) is studied, forming a rod-coil structure. The aggregate nanodomains and intra-aggregate dynamics correlate well as two-parameter aggregate (200x400 nm) and two relaxation channels of 6.9 ps and 12.0 ps and with one-parameter aggregate (1000x1000 nm) and one relaxation channel of 5.3 ps. The interaction with [6,6]phenyl-C61-butyric acid methyl ester (PCBM) is of donor-acceptor interest. The ST/PCBM fluorescence spectra from the solution:film result in a spectral red shift of 60 nm and intensity decrease with a ratio of 17:8, respectively. The fluorescence decay times ?1 increase with increasing PCBM concentration from 17.0 ps to 25.5 ps and from 5.8 ps to 19 ps in the solutions and the films, respectively. Interestingly, the decay time ?2 result for the solutions and for the films to be on average 491 ps and 78 ps, describing the slower and the faster overall process, respectively. Excitation energy transfer between ST and PCBM is observed as the radiative quenching and the static quenching through the disaggregation of the ST aggregates by PCBM molecules.

  1. Tibor Palszegi, Jan Sepelak, Eduard Jane, Daniel Repovsky, Vojtech Szoecs, Ignac Bugar, Gabriel Cik, Dusan Velic: Correlation of nanodomain morphology and ultrafast fluorescence dynamics in bisdecylsexithiophene-polyethylene oxide copolymer film, Journal of Photochemistry and Photobiology A: Chemistry - Vol. 343, (2017), 103–111
  2. Marianna Gregova Trencanová, Daniel Repovsky, Maria Lujza Marcakova, Ludovit Haizer, Vojtech Szoecs, Ines Miranda , Carlos Manuel Melo Pereira, Gabriel Cik, and Dusan Velic: Fluorescence Dynamics of Thiophene-based Copolymer/Fullerene-derivative System as Solution and Blend Film, in press