An Interfacial and Bulk Charge Transport Model for Dye-Sensitized Solar Cells Based on Photoanodes Consisting of Core–Shell Nanowire Arrays

Abstract

Dye-sensitized solar cells (DSSCs) based on ordered photoanode morphologies, such as nanotubes and nanowires, are widely gaining attention because these geometries are believed to enhance interfacial charge transfer and bulk charge transport. Unfortunately, experimental results have yet to show substantial improvement to conversion efficiency over nanoparticle-based DSSCs. A model is developed to characterize the performance of an idealized photoanode based on an ordered array of transparent conductive nanowires coated with an anatase titania shell. The role of the interfacial electric field in nanowire-based DSSCs is explored computationally by turning electron migration ON or OFF. The results show that back-reaction rates are most strongly influenced by the electric field. These electron loss mechanisms can be reduced by several orders of magnitude, leading to improvements in short-circuit current, open-circuit voltage, and fill factor.