Regensburg 2016 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 30: Poster: Organic Electronics and Photovoltaics
CPP 30.36: Poster
Dienstag, 8. März 2016, 18:15–21:00, Poster B2
Modeling the Exciton Diffusion in Flat Heterojunction Organic Solar Cells — •Karl-Philipp Strunk1,2, Thomas Pfadler1, and Lukas Schmidt-Mende1 — 1Universität Konstanz, Konstanz, Germany — 2Centre of Advanced Materials, Heidelberg, Germany
Organic solar cells have proven themselves to be a promising candidate towards a more energy efficient future. The performance of flat heterojunction solar cells is limited by the exciton diffusion length LD of the active materials. For this reason exact knowledge of LD is of significant importance when comparing different organic semiconductors. In this work, an organic system with state-of-the-art performance employing an exciton blocking layer of Tris[4-(5-phenylthiophen-2-yl)phenyl]amine (TPTPA) is studied. Based on experimental and simulated external quantum efficiency (EQE) spectra, it is shown that TPTPA contributes to the photocurrent, although exciton blockers are commonly believed to be non-photoactive. EQE spectra are simulated using a transfer matrix approach and a generalized diffusion equation for the exciton density, following previous publications. Furthermore, simulated EQE spectra are fitted to experimental data to obtain values of LD for both donor and acceptor. LD of the donor is measured experimentally using a time-resolved photoluminescence technique. The good agreement of experimentally and computationally obtained exciton diffusion lengths proves the selected algorithm to be a unique way to determine LD from measurements of complete devices along with material characterization and simulations.