Electrochemical growth of ZnO nanocolumn arrays and ZnO mesoporous films

摘要

Electrodeposition is a versatile method for the synthesis of ZnO thin films. Various nanostructures can be prepared in a controlled manner. The formation of ZnO nanowire arrays is observed in a deposition bath depleted in zinc salt precursor. Compared to dense ZnO films, the ZnO nanowire arrays present a high UV near band edge PL emission due to a better structural quality with lower structural defects. Recent works assign the formation of ZnO nanowires to the increase in the interfacial pH during the growth. At high pH, zinc ions are complexed by hydroxide ions and are negatively charged. This leads to the quenching of the lateral growth and the slowdown of the vertical growth rate. Mesoporous ZnO films can be prepared by electrodeposition by using a structure directing agent. Results obtained with eosin Y dye are interesting : after optimizing of the dye concentration, a maximum porosity of more than 62% and a maximum of specific surface area of 75 m~2.cm~(-3) is obtained. These films are promising for photocatalysis and solar cell applications.