Influence of Inorganic Binder Composition on the Structure-Property Relationship of Monolithic Dye-sensitized Solar Cells with Carbon-based Counter Electrode

Abstract

In order to fabricate a low-cost dye-sensitized solar cell (DSSC), carbon has become a highly preferred catalytic material as counter-electrode, particularly for DSSC with monolithic structure. This paper presents novel synthesis method of carbon-based composite pastes using two types of carbon material, i.e. carbon nanopowder and activated carbon. The concentrations of the inorganic binder added to the composite pastes were varied to investigate their effect on the physical properties of the counter electrode and the electronic properties of the constructed monolithic DSSC. The inorganic binder used in this work was titanium dioxide nanoparticles, Evonik P25. After optimization, power conversion efficiency of 0.221% was achieved by the monolithic DSSC with counter electrode composite comprising activated carbon and titanium dioxide with weight concentration of 0.5 g and 0.25 g, respectively. Characterizations using gas sorption technique showed that the shape of the hysteresis curves obtained for all composites resembled the isotherm curve Type II and H3, indicating the presence of micropores. Furthermore, higher concentration of titanium dioxide nanoparticles as binder led to counter electrode with lower surface area. The solar cell efficiency, however, was found to be not only correlated to the surface area or the binder composition, but it was also determined by the type of the carbon material.