Jakub Rysz oral presentation (OB1-Thu1-1-2)
SIMS studies on the interdiffusion of organic donors and acceptors under solvent vapor annealing
1 Jagiellonian University - Institute of Physics, Łojasiewicza 11, 30-348 Kraków, Poland
2 Academic Centre for Materials and Nanotechnology - AGH University of Science and Technology, al. Mickiewicza 30, 30-049 Kraków, Poland
3 Faculty of Physics and Applied Computer Science - AGH University of Science and Technology, al. Mickiewicza 30, 30-049 Kraków, Poland
Organic solar cells are very attractive sources of green energy due to many reasons but the two most important are: i) mechanical properties, typical for polymers, and ii) low production cost. The most efficient organic photovoltaic devices (OPV) have a structure of interpenetrating domains of donors and acceptors. Engineering of this structure, called bulk heterojunction (BHJ) , is one of the most crucial task in developing of highly efficient devices. So far, BHJ structures were obtained by the phase separation process or by interdiffusion within a bilayer at elevated temperatures .
Recently we have shown that interdiffusion of fullerene derivative called PCBM (acceptor) into semiconducting polymer layer (donor) can be triggered by exposure to solvent vapors. This process is called solvent vapor annealing . Starting from polymer/PCBM bi-layers completely interdiffused films can be obtained within a few minutes. Time of exposure (time of solvent annealing), type of the solvent and partial pressure of solvent vapors under the sample are the key parameters influencing formation of interpenetrating domains of donors and acceptors.
In this work we present the recent results of our studies on the interdiffusion of organic donors and acceptors. The dynamic mode of Secondary Ion Mass Spectrometry gave us the direct insight into the evolution of polymer/PCBM bi-layers under solvent vapor annealing, while images obtained in static mode showed the extent of lateral diffusion.
This work was financially supported by National Science Center Poland (grant UMO-2013/11/B/ST504473). The research was carried out with equipment purchased thanks to financial suport of the European Regional Development Fund in the framework of the Polish Innovation Economy Operational Program (contract no. POIG.02.02.00-12-023/08)
 G. Yu; J. Gao; J. C. Hummelen; F. Wudl; A. J. Heeger Science 270, 1995, 1789
 Treat N, Brady M, Smith G, Toney M, Kramer E, Hawker C, and Chabinyc M. Advanced Energy Materials 1(1), 2011, 82-89
 Y. Zhao, Z. Y. Xie, Y. Qu, Y. H. Geng, L. X. Wang, L. X. Appl. Phys. Lett. 90, 2007, 043504