Dresden 2009 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 33: Organic Photovoltaics II
CPP 33.2: Vortrag
Donnerstag, 26. März 2009, 14:15–14:30, ZEU 222
Investigation of the preparation process of dye sensitized photovoltaic cells by AFM, Kelvin Probe Force Microscopy and X-ray diffraction — •Harald Graaf1, Carsten Mädler1, Mirko Kehr1, and Torsten Oekermann2 — 1Institute of Physics, University of Technology Chemnitz, 09107 Chemnitz, Germany — 2Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover, 30167 Hannover, Germany
Dye-sensitized photovoltaic cells with zinc oxide (ZnO) as the inorganic semiconductor and organic dye molecules as the sensitizer are well known devices with high efficiency. Such cells are prepared by electrochemical deposition of an aqueous zinc salt solution including dye molecules. After deposition the dye is desorbed to obtain a porous ZnO network followed by re-adsorption of the dye as a sensitizer. Up to now studies concerning the influence of different processing steps on the structure of the ZnO are sparse. We discuss the growth mechanism during film deposition and the crystal structure changes of the ZnO accompanying the desorption process, which is performed in an alkaline aqueous solution. X-ray investigation shows the influence of the dye on the structure of the formed ZnO/dye hybrid film. AFM topography and Kelvin Probe Force Microscopy investigations suggest the following deposition process: at first dye molecules are adsorbed on the electrode followed by ZnO formation within the pores of the organic network. This ZnO, which shows high crystallinity, seems to be oriented with the zinc face up.