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O: Fachverband Oberflächenphysik
O 101: Molecular Films: Electronics, Photovoltaics and Structure
O 101.2: Talk
Friday, April 4, 2014, 10:45–11:00, WIL A317
Nanometer Scale Optical and Photocurrent Microscopy of Organic Optoelectronic Materials — Marius van den Berg, Kai Braun, Alfred J. Meixner, and •Dai Zhang — Institute of Phyiscal and Theoretical Chemistry, University of Tübingen, Tübignen
Optoelectronic material is the basic component in photovoltaic, photodetector, or transistor system. In organic photovoltaic, the photon-electron conversion efficiency is strongly influenced by the local donor/acceptor morphology, such as crystallinity, or domain size [1, 2]. To get insight into this topic, we monitor the absorption and photocurrent from organic semiconductor blends using a home-built white light transmission setup. To image the distributions and local morphology of donor or acceptor materials, we use Raman and photoluminescence spectroscopy combined with a parabolic mirror assisted confocal optical microscope. Such optical signals can be correlated with topography information through an integrated shear-force scanning probe microscope. The intensity ratios between the donor photoluminescence and the local photocurrent under different bias voltages will be discussed, with respect to the charge transfer processes. Furthermore, photodegradation of the optoelectronic materials will be systematically compared, regarding the changing of photoluminescence, and Raman signals as well as the photocurrent decays.
References: [1] Zhang, D., Heinemeyer, U., Stanciu, C., et al, Phys. Rev. Lett., 2010, 104, 056601. [2] Wang, X., Azimi, H., Zhang, D., et al, Small, 2011, 7, 2793.