Layer-by-layer self-assembled mesoporous PEDOT–PSS and carbon black hybrid films forplatinum free dye-sensitized-solar-cell counter electrodes

Abstract

A thin film of poly(3,4-ethylenedioxythiophene)–poly(4-styrenesulfonic acid) (PEDOT–PSS),which is an alternative cathodic catalyst for Pt in dye-sensitized solar cells, was preparedusing the layer-by-layer self-assembly method (LbL). The film is highly adhesive to thesubstrate and has a controllable thickness. Therefore, the PEDOT–PSS film prepared usingLbL is expected have high performance and durability as a counter electrode. Moreover,when carbon black was added to the PEDOT–PSS solution, highly mesoporousPEDOT–PSS and carbon black hybrid films were obtained. These films showed highcathodic activity. In this study, we investigated the change in morphology in the obtainedfilm with increasing carbon black content, and the influence of the porosity and thicknesson the performance of the cells. In this study, a Pt-free counter electrode with performancesimilar to that of Pt-based counter electrodes was successfully fabricated. Theachieved efficiency of 4.71% was only a factor of 8% lower than that of the cell usingconventional thermally deposited Pt on fluorine-doped tin oxide glass counter electrodes.