New Materials Department, CIDETEC, Centre for Electrochemical Technologies, Parque Tecnológico de San Sebastián, Paseo Miramón 196, Donostia-San Sebastián 20009, Spain
Solvionic, Chemin de la Loge, Toulosse 31078, France
In the framework of ORION project, CIDETEC and SOLVIONIC put together their wide expertise in electrochemical processes and ionic liquid synthesis to develop an innovative ZnO deposition route. The approach is based on the electrochemical reduction of O2 in an aprotic room temperature ionic liquid containing Zn2+ cations. The aprotic character of the ionic liquids is essential to avoid any interference and/or intermediate step related to metal hydroxide phases, which generally occurs in aqueous media. ZnO films are thus formed by a new reaction way. In addition, the interaction between ionic liquid moieties and ZnO surfaces seem to play a crucial role in the deposition mechanism, affecting the packing and ordering of ZnO nanocrystals. As a result, unusual non-polar oriented ZnO nanocrystalline films have been obtained. The films exhibit semiconducting behavior and room temperature photoluminescence emission.
All in all, the great potential of ionic liquids based electrolytes for the electrodeposition of functional optoelectronic ZnO nanocrystalline thin layers with innovative microstructural properties has been demonstrated. The present results may have a significant impact in several fields because the electrodeposition approach may be extrapolated to other metal oxides.
