Honeycomb-like poly(3,4-ethylenedioxythiophene) as an effective and transparent counter electrode in bifacial dye-sensitized solar cells

Abstract

Honeycomb-like poly(3,4-ethylenedioxythiophene) (PEDOT) counter electrode (CE) for the bifacial dye-sensitized solar cell (DSSC) is first prepared by a facile method using a sacrificial template of poly(methyl methacrylate) (PMMA). Cyclic voltammetry and ultraviolet–visible spectrophotometer measurements indicate that the PEDOT CE with honeycomb-like nanostructure demonstrates excellent electrocatalytic activity for the reduction of triiodide (I3−) to iodide (I−) and high transparency for the backside illumination. Electrochemical impedance spectroscopy measurements show that the honeycomb-like nanostructure reduces the CE's resistance for the transfer of electrons from the external circuit back to the redox electrolyte. The bifacial DSSC based on the honeycomb-like PEDOT CE yields front and rear efficiencies of 9.12% and 5.75%, which are higher than those of the bifacial DSSC based on the flat PEDOT (8.05% and 3.78% respectively). These promising results highlight the potential application of the facile template method for preparing other cost-effective and transparent CEs, which can be used in bifacial solar cells and tandem devices.