Dresden 2014 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 102: Sustainable photovoltaics with earth-abundant materials II (organized by DS)
HL 102.1: Vortrag
Donnerstag, 3. April 2014, 15:00–15:15, CHE 91
Electroless deposition of porous zinc oxide films on sheets of aluminium — •Stephanie Künze and Derck Schlettwein — Institute of Applied Physics, Justus-Liebig-University Giessen, Germany
Metal foils, wires or metalized polymer fibres are of interest as substrate electrodes for porous wide band-gap semiconductors in dye-sensitized solar cells (DSC) if protected against corrosion by a passivating oxide layer. Here, aluminium sheets were used to deposit porous zinc oxide for DSC. For the deposition of ZnO, the natural insulating Al2O3 layer on Al was removed by chemical etching in hydrochloric acid (HCl). A subsequent treatment in alkaline zinc hydroxide (zincate stain) was used to grow Zn in order to protect the metal and to provide a reactive surface for the deposition of ZnO. Porous ZnO films were then prepared by electroless deposition without any electrical connections on such pre-treated Al substrates from aqueous ZnCl2 saturated with O2. The xanthene dye EosinY was used to form pores in the growing crystalline ZnO. The film thickness of porous ZnO and the coverage of the metal surface increase with the deposition time and with the amount of Zn from the pre-treatment. These results were contrasted with the results from electrochemical depositions at an applied potential under otherwise identical conditions. For comparison purposes, depositions of porous zinc oxide on etched sheets of Zn were analyzed to provide a virtually unlimited supply of Zn. Al and Zn unlike other elements often used in photovoltaics offer the chance of large-scale applications since both are abundant on earth.