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DS: Fachverband Dünne Schichten
DS 41: Focus Session: Sustainable Photovoltaics with Earth Abundant Materials II
DS 41.4: Talk
Thursday, April 3, 2014, 15:45–16:00, CHE 91
Improved Anchoring of Indoline Dyes for the Sensitization of ZnO — Felix Fiehler1, •Jane Falgenhauer1, Melanie Rudolph1, Christoph Richter1, Hidetoshi Miura2, and Derck Schlettwein1 — 1Institute of Applied Physics, Justus-Liebig-University Giessen, Germany. — 2Chemicrea Inc, Iwaki, Fukushima, Japan.
D149 is a well-established indoline dye for the sensitization of ZnO. Although high efficiencies can be obtained, the dye partly desorbs from the ZnO surface in contact with the redox electrolytes in dye-sensitized solar cells. Similar indoline dyes with a second carboxylic binding group at the molecule to attach to the ZnO surface showed higher stability [1]. In this work, sandwich-cells were built with electrodeposited ZnO on conductive glass as the working electrode which was sensitized with D149 or D149-derivatives DN91, DN216 and DN285 having two binding groups of different length of a hydrocarbon spacer. Current-voltage curves and dynamic measurements like electrical impedance spectroscopy at AM1.5 illumination and intensity-modulated photovoltage/photocurrent spectroscopy (IMVS/IMPS) were performed. The observed shift of effective band positions, the recombination resistance and the observed lifetime of the excited state were found to be comparable for the different sensitizers. DN216, however, showed higher photocurrent densities than the D149 reference and the cell characteristics were more reproducible. Implications for the future development of dye-sensitized solar cells based on solution-processed ZnO will be discussed. [1] J. Falgenhauer, C. Richter, H. Miura, D. Schlettwein Chem. Phys. Chem., 13, 2893-2897 (2012).