The impact of a TiO2/r-GO composite material on the performance of electron transport electrodes of dye sensitized solar cells.

Abstract

In dye sensitized solar cells, the role of the electron transport layer is crucial because it makes it easier for photo-generated electrons to get from the dye to the external circuit. In DSSCs, the utilization of TiO2 is likely to be given preference in the production of electron transport electrodes due to its notable characteristics such as its expansive surface area, porosity, and capacity to scatter light. Nevertheless, the presence of heterogeneity within the mesoporous structure increases the likelihood of TiO2 aggregation, which subsequently diminishes the beneficial impact of TiO2 on the performance of DSSCs. In this context, reduced graphene oxide (r-GO) is introduced as an additive into the TiO2 network during the preparation of TiO2/reduced graphene oxide (r-GO) composites. The integration of r-GO with TiO2 has been recognized as a promising approach to enhance electron transport and electron lifespan, owing to remarkable qualities exhibited by r-GO. The present investigation involved the synthesis of a composite material including titanium dioxide/reduced graphene oxide (TiO2/r-GO) through the utilization of the co-precipitation technique. Following this, the generated TiO2/r-GO composite material and pure TiO2 were deposited on FTO through electrophoretic deposition to obtain an electron transport electrode of a dye sensitized solar cell. It should be noted that when r-GO was combined with TiO2, the performance of DSSCs improved notably compared to pure TiO2. As a result, the findings of this work have significant implications for the advancement of the TiO2/r-GO composite deposited through electrophoretic deposition. The power conversion efficiency reached 6.64% with the addition of r-GO in the metal oxide electron transport electrode. The obtained findings align with the outcomes of electrochemical impedance investigations in which the electrode constructed with TiO2/r-GO exhibits reduced electron transport resistance (RCt) at the anode/dye/electrolyte interface, as well as lower overall resistance (Rtotal) in comparison to TiO2-based DSSCs. These advancements have the potential to be employed in commercial DSSC manufacturing.