About Establis

Earth receives enough sunlight in one hour to satisfy all human needs in a year. Using solar energy will reduce harmful CO2 emissions and resolve the forthcoming energy deficit. The market for stable, mass-produced Organic Solar Cells is estimated at one billion Euros by 2016.

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ESTABLIS will train a team of 11 PhDs and 4 Postdocs to become the scientific leaders in industry and academia. ESTABLIS Fellows will excel.

Research on organic solar cells

Complementarity is at the heart of Establis. To develop Organic Solar Cells requires a concerted combination of physical, synthetic and modelling capabilities. Establis members are working together–across preconceived scientific boundaries–to accelerate the production of Organic Solar Cells.

Partnerships & collaborations

Our Industrial Partners and Associate Partners ensure that the training and technology is economically feasible.

EU support

The EEC is constructively investing more than 3.9 M€ in Establis to train, research and collaborate at the highest international level and ensure our energy platform for the 21st century.

Scientific results

15th International Symposium on “Ultrafast Phenomena in Semiconductors” (15-UFPS) - Mobility and recombination of the charge carriers in the organic bulk heterojunctions with different compositions

Mobility and Recombination of the Charge Carriers in the Organic Bulk Heterojunctions with Different Compositions

Meera Stephen, Julius Važgėla, Kristijonas Genevičius, Gytis Juška, Kęstutis Arlauskas

Department of Solid State Electronics, Vilnius University, Saulėtekio 9 III k., 10222 Vilnius, Lithuania, This email address is being protected from spambots. You need JavaScript enabled to view it.

Presented at 15th International Symposium on “Ultrafast Phenomena in Semiconductors” (15-UFPS), in Vilnius, held from Aug 25-28, 2013

Due to the simple solution processing organic semiconductors are promising materials for large area applications such as solar cells. The recombination rate, charge carrier mobility and photogeneration efficiency are the main parameters which determine the efficiency of an organic solar cell. One of the crucial efforts towards increasing photocurrents is the use of the bulk heterojunction systems where exitons have higher chance to reach the donor-acceptor junction. The typical recombination mechanism in organic semiconductors is bimolecular Langevin recombination. In this case the recombination rate is determined by the possibility for the charge carriers to meet each other, so it directly depends on charge carrier’s mobility. The regioregular poly(3-hexylthiophene) and phenyl-C61-butyric acid methyl ester (RR-P3HT and PCBM) heterojunction cells are widely studied because of its unique morphology leading to a different recombination mechanism1, the only drawback of such systems is the low open circuit voltages. Silicon-bridged bithiophene (Si-PCPDTBT) has recently emerged as a novel low band-gap polymer for photovoltaic applications due to many of its desirable characteristics2.

In this work we present results we obtained in bulkheterojunctions of Si-PCPDTBT : PCBM and Si-PCPDTBT : PCBM : RR-P3HT with different compositions. From photogenerated charge carriers density relaxation measured by photo-CELIV, we conclude that in bulk heterojunctions of Si-PCPDTBT : PCBM, recombination does not follow the typical Langevin mechanism.


 1 G. Juška, K. Genevičius, N. Nekrašas, and G. Sliaužys, Phys. Stat. Sol. C, 7, 3–4, 980–983 (2010).

2 T. M. Clarke, D. B. Rodovsky, A. A. Herzing, J. Peet, G. Dennler, D. DeLongchamp, C. Lungenschmied, and A. J. Mozer,  Adv. Energy Mater, 1, 6, 1062–1067 (2011).