722aw Inverse Opal Topology of TiO2 Electrodes for Photoelectrochemical Cells

Sonia S. Mathew and Ilona Kretzschmar. Dept. of Chemical Engineering, City College of New York, New York, NY 10030

Harnessing solar energy with inexpensive materials and manufacturing methods is an important challenge in today's energy market. A dye-sensitized solar cell (DSC) is a photo-electrochemical device that uses cheap electrodes like TiO2. It has been demonstrated that adding order to the TiO2 layer of a DSC improves the efficiency of the cell, by reducing electron recombination events [1]. Using this idea, Mor et. al. synthesized electrodes using TiO2 nanotube arrays. In our research, we are investigating TiO2 electrodes that have an inverse opal topology. Such structures are ordered and provide a (comparatively) larger surface area, which allows higher concentrations of adsorbed dye per unit area. It also provides close contact between the dye-TiO2 anode and the electrolyte. Using the method of colloidal self-assembly, we have prepared TiO2 electrodes that have pores in a hexagonal pattern. These electrodes are prepared by assembling polystyrene particles into molds, and subsequently infiltrating them with a polymer-TiO2 mixture. The cured polymer-TiO2-polystyrene film is washed with solvent to remove the polystyrene templates, resulting in a porous film. In this poster, we will report the mechanical, optical, and electrical properties of both porous and non-porous TiO2-polymer films.

[1] G. K. Mor, K. Shankar, M. Paulose, O. K. Varghese and C. A. Grimes, Nano Lett., 2006, 6, 215