Dresden 2009 – wissenschaftliches Programm
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SYOP: Symposium Organic Photovoltaics: From Single Molecules to Devices
SYOP 4: Organic Photovoltaics: from Single Molecules to Devices
SYOP 4.56: Poster
Donnerstag, 26. März 2009, 16:30–19:00, P1A
CT-State Dissociation and Charge Recombination in OPVs — •Roger Häusermann1, Nils Reinke1, Evelyne Huber1, Thomas Flatz2, Michael Moos2, and Beat Ruhstaller1 — 1ZHAW, Inst. of Computational Physics, Winterthur, Switzerland — 2Fluxim AG
The dissociation of the charge-transfer-state (CT) into free charge carriers is a very important process in the modeling of OPVs. A theoretical description of this mechanism has been developed by Onsager and Braun. The implications of this theory in real OPVs is not completely clear. Recently there was the proposition to reduce the whole device physics to the mechanisms at the donor-acceptor interface. This has been verified for a wide range of OPV materials, but it also raises questions about the universality of this simplification.
In this study we developed a comprehensive device simulator. Our simulations have shown that a good agreement with measured J-V curves can be found by omitting any dissociation mechanism but at the same time increasing the influence of the Langevin recombination. This shows that distinct features of J-V curves are multi-causal and therefore a simplification by leaving out some of the mechanisms leads to an overestimation of the influence of other processes.
We present the influence of the input parameters (CT-state dissociation, recombination and mobility) on the J-V curves and discuss in detail where and if each parameter can be seen separately in the shape of the J-V curve. The contributions of the different loss mechanisms, namely decay of excitons and CT-states as well as charge recombination will be addressed as function of material properties.