Berlin 2012 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 24: Poster: Organic Semiconductors
CPP 24.27: Poster
Wednesday, March 28, 2012, 11:00–13:00, Poster A
Influence of intermolecular gap and film morphology on the open circuit voltage of organic heterojunction solar cells — •Ulrich Hörmann1, Julia Wagner1, Mark Gruber1, Andreas Opitz2, and Wolfgang Brütting1 — 1Institute of Physics, University of Augsburg, Germany — 2Institute of Physics, Humboldt University of Berlin, Germany
The efficiency of a photovoltaic cell is directly proportional to its open circuit voltage. This in turn is eventually set by the intermolecular gap, i.e. the energy of the donor-acceptor charge-transfer state in organic solar cells. In this contribution we introduce diindenoperylene (DIP) as a new molecular acceptor and compare it to C60 in planar heterojunction cells. Being able to deliberately change the morphology of the molecular films by varying the substrate temperature during the growth process, we demonstrate that the Voc not only scales with the intermolecular gap but also strongly depends on the morphology of the organic films. We show that planar heterojunctions of thiophene derivatives and DIP yield extraordinarily high open circuit voltages of approximately 1.2 V for poly(3-hexylthiophene) and almost 1.4 V for heat treated α-sexithiophene [1]. Those values are close to the maximum Voc attainable for these material systems.
[1] U. Hörmann et al., phys. stat. sol. RRL 5 (2011) 241