(107f) Inverse Opal Topology of Titania Electrodes for Photovoltaics

Dye-sensitized solar cells use porous titania photoanodes to convert solar energy to usable work. Traditionally, the titania electrode is a randomly connected network of titania nanoparticles.  This configuration, while it maximizes the surface area for dye-adhesion, which in turn maximizes the amount of energy harnessed, is also prone to excessive recombination.  Our approach is to improve the efficiency of the DSSC is by minimizing these recombination events by introducing order to the titania electrode.  Our electrode is made of titania inverse opals with pore sizes on the order of 100s nm, compared to <20 nm in the current setup.  This configuration avoids incomplete filling of the pores, which hampers the electron transfer across the interface, contributing to recombination.  

These electrodes are prepared by assembling polystyrene particles into molds, and subsequently infiltrating them with a TiO₂ precursor.  We will discuss the methods used to fabricate titania inverse opals of a range of pore sizes, and present the advantages and disadvantages of each of them.  We will also present some preliminary electrochemical analysis of these electrodes.