High efficiency dye sensitized solar cells using ionic liquid electrolytes

I&EC 261

Daibin Kuang, daibin.kuang@epfl.ch, Seigo Ito, seigo.ito@epfl.ch, Shaik Mohammed Zakeeruddin, shaik.zakeer@epfl.ch, and Michael Graetzel, michael.graetzel@epfl.ch. Department of Chemistry, Swiss Federal Institute of Technology Lausanne, Laboratoire de Photonique et interfaces, Ecublens, Lausanne, CH 1015, Switzerland
Nanocrystalline dye sensitized solar cells (DSC) are attracting considerable academic and industrial interest as low-cost, high efficiency alternatives to the conventional solid p-n junction photovoltaic devices. Encapsulation of volatile electrolyte is a critical issue in view of the practical applications. A viable solution to this problem is replacement of organic solvent electrolytes by ionic liquid electrolytes, whose vapor pressure is negligible. Ionic liquids with good chemical, thermal stability and wide electrochemical window have been recently pursued as alternative electrolytes for DSC. Iodide based ionic liquids are more viscous than conventional organic solvents. To reduce the viscosity of these electrolytes to some extent a binary ionic liquid electrolytes prepared by mixing iodide based ionic liquids with low viscosity ionic liquids (having weakly coordinating anion based ionic liquids). Here we report a new family of novel ionic liquids with low viscosity to obtain high efficiency and device stability at elevated temperatures. This lecture will summarize the most recent developments in the use of ionic liquid electrolytes for DSC.