Dresden 2014 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 34: Poster Session
MM 34.36: Poster
Tuesday, April 1, 2014, 18:00–20:00, P4
Lateral Resolved EELS on organic bulk heterojunctions - a low-dose approach to optimized spatial and energy resolution in the TEM — •Anne K. Kast1,2,3, Martin Pfannmöller1, Marco Oster1, Philipp Wachsmuth4, Ralf Hambach4, Gerd Benner5, Diana Nanova2,3, Robert Lovrincic2,3, Wolfgang Kowalsky2,3, Ute Kaiser4, and Rasmus R. Schröder1,3 — 1Cryo-EM, Universitätsklinikum Heidelberg — 2IHF, TU Braunschweig — 3innovationLab GmbH, Heidelberg — 4Materialwissenschaftliche EM, Uni Ulm — 5Carl Zeiss GmbH, Oberkochen
We implement a novel analytical method using EFTEM which allows visualizing donor and acceptor materials in organic solar cell thin films by analyzing electronic excitations features in the optical and plasmonic energy region. Segmentation by EELS reveals that these carbon based materials show characteristic optical excitations in energy-loss spectra. However, the blend materials are very sensitive to radiation damage, which impedes spatial spectral mapping using EELS in conventional scanning beam mode. We introduce an automated scheme that exploits the inherent spatial resolution in the EEL spectrum as it is obtainable from aberration corrected imaging energy filters. It involves automatic scanning of the image of a slit aperture in the illumination beam path. To eliminate residual image distortion in the EEL spectrum we apply correction algorithms for quantitative spectrum interpretation. Application of such automated laterally resolved EEL spectroscopy allows spatial mapping of high-resolution spectra in two dimensions at low-dose conditions.