Berlin 2008 – scientific programme
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SYSA: Symposium Tayloring Organic Interfaces: Molecular Structures and Applications
SYSA 5: Poster Session SYSA
SYSA 5.31: Poster
Tuesday, February 26, 2008, 14:30–20:00, Poster A
Light incoupling in small molecule organic solar cells — •Nikola Allinger1, Jan Meiss1, Moritz Riede1, Karl Leo1, and Wolf-Michael Gnehr2 — 1Institut für Angewandte Photophysik, Technische Universität Dresden, 01069 Dresden (Germany) — 2Heliatek GmbH, Liebigstraße 26, 01187 Dresden (Germany)
Light incoupling is an essential topic for optimization of organic solar cells. In our group, we examine light incoupling of different kinds of transparent contacting materials as well as external dielectric coatings, using optical simulation of thin film systems and experimental methods. Thin films of small molecules are prepared by thermal evaporation in a multi-chamber UHV system. Complex refraction indices of various materials are calculated from reflection and transmission measurements of monolayers. For modelling of optical properties of thin film systems, we developed a numerical simulation program based on the transfer matrix method. The cell structures investigated consist of nanolayers of small molecules, using ZnPc/C60 as an acceptor-donor heterojunction. As contact materials, we compare the expensive standard material indium tin oxide (ITO) with more cost-efficient alternatives like thin Ag layers or spin-coated layers of the polymer PEDOT:PSS, and discuss the resulting cell properties. Additional dielectric layers of varying materials, like tris(8-hydroxy-quinolinate)-aluminum (Alq3) or N,N'-tetrakis(4-methoxyphenyl)-benzidine (MeO-TPD), are deposited on top of the stack and their influence on cell efficiencies is investigated.