Regensburg 2013 – scientific programme
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O: Fachverband Oberflächenphysik
O 76: Focussed Session: Solid-liquid Interfaces II
O 76.9: Talk
Thursday, March 14, 2013, 18:45–19:00, H31
Electroless deposition of porous zinc oxide films on aluminium — •Stephanie Künze and Derck Schlettwein — Institute of Applied Physics, Justus-Liebig-University Giessen, Germany.
Porous zinc oxide is discussed as an active semiconductor in dye-sensitized solar cells. Metal substrates are of interest to provide excellent conductivity and mechanical flexibility of cells. Metal substrates that are protected by an oxide layer in contact to air (passivated metal) can lead to cells containing even an iodide-containing electrolyte without the danger of corrosion. Aluminium can serve as such a metal substrate. Sheets of aluminium were pre-treated in highly-concentrated hydrochloric acid and subsequently in an alkaline zinc hydroxide solution (zincate stain). A coat of zincate was left on the aluminium surface. Porous zinc oxide films were prepared by electroless deposition on such pretreated planar aluminium substrates in the presence of the xanthene dye EosinY by two methods. Either a zinc-chloride solution saturated with oxygen or an aqueous solution of 0.1 M Zn(NO3)2 was used. The growth of zinc oxide was characterized by optical microscopy, scanning electron microscopy (SEM) and a stylus method to determine the layer thickness. The difference between the two forms of deposition is reported and a mechanism for this electroless deposition on aluminium is proposed and will be discussed. The influence of the amount of deposited zincate from the pre-treatment on the film thickness of the porous zinc oxide and the coverage of the metal surface is shown. In this context also results of an electroless deposition of porous zinc oxide on etched sheets of zinc was analyzed.