α-Fe2O3/Reduced Graphene Oxide Composites as Cost-Effective Counter Electrode for Dye-Sensitized Solar Cells

The counter electrode (CE) is an important and vital part of dye-sensitized solar cells (DSSCs). Pt CEs show high-performance in DSSCs using iodide-based electrolytes. However, the high cost of Pt CEs restricts their large-scale application in DSSCs and the development of Pt-free CE is expected. Here, alpha-Fe2O3/reduced graphene oxide ( alpha-Fe2O3/RGO) composites are prepared as the Pt-free CE materials for DSSCs. A simple hydrothermal technique was used to disseminate the alpha-Fe2O3 solid nanoparticles uniformly throughout the RGO surface. The presence of the alpha-Fe2O3 nanoparticles increases the specific surface area of RGO and allows the composites to be porous, which improves the diffusion of liquid electrolyte into the CE material. Then, the electrocatalytic properties of CEs with alpha-Fe2O3/RGO, alpha-Fe2O3, RGO, and Pt materials are compared. The alpha-Fe2O3/RGO CE has a similar electrocatalytic performance to Pt CE, which is superior to those of the pure alpha-Fe2O3 and RGO CEs. After being fabricated as DSSCs, the current-voltage measurements reveal that the DSSC based on alpha-Fe2O3/RGO CE has a power conversion efficiency (PCE) of 6.12%, which is 88% that of Pt CE and much higher than that of pure alpha-Fe2O3 and pure RGO CEs. All the results show that this work describes a promising material for cost-effective, Pt-free CEs for DSSCs.