Surface passivation of titanium dioxide via an electropolymerization method to improve the performance of dye-sensitized solar cells

Abstract

In dye-sensitized solar cells recombination reactions at the TiO₂ photoanode with the electrolyte interface plays a critical role in cell efficiency. Recombination of injected electrons in the TiO₂ with acceptors in the electrolyte usually occurs on uncovered areas of TiO₂ surfaces. In this work, we report electropolymerization of polymer films on nanoporous TiO₂ electrode surfaces using an ionic liquid as the growth medium. The choice of ionic liquid as the growth medium for this study is based on the insolubility of dye N719 in this electrolyte, thus avoiding dye molecule detachment from the TiO₂ photoanode surface over the entire potential range investigated during the electropolymerization. Consequently using this insulating and passivating polymer on the open areas of a nanoporous TiO₂ surface the photovoltaic device efficiency most improved by 19%, furthermore, preventing detachment of dye molecules leads to an increase in stability of the dye-sensitized solar cells.