Dye-sensitized solar cells with 3D flower-like α-Fe2O3-decorated reduced graphenes oxide as photoanodes

For the first time, we report a one-step fabrication of an environment-friendly approach to synthesize flower-like alpha-Fe2O3 hierarchical nanoparticles (NPs)/reduced graphene oxide (RGO) hybrids by combining the graphene oxide (GO) with the growth of alpha-Fe2O3 NPs. The GO sheet which possesses the functional group, such as hydroxyl (-OH) and carbonyl groups (-OOH), can be easily incorporated with the petal of the flower-like alpha-Fe2O3 in ethanol and water solution through a solvothermal process, during which GO is reduced to RGO without the addition of any strong reducing agent or requiring any post-high-temperature annealing process. The as-prepared samples are loose and porous with flower-like structure, and the RGO hybrids were wrapped up uniformly on the sheet of alpha-Fe2O3 NPs. To demonstrate the potential applications, we have fabricated dyesensitized solar cells (DSSCs) from the as-synthesized hierarchical flower-like alpha-Fe2O3/RGO and investigated it for the photoanode of DSSCs. Results show that the hierarchical alpha-Fe2O3/RGO solar cell exhibits improved performances in comparison with the free alpha-Fe2O3 NPs. The enhancement of photovoltaic properties is attributed to the unique porous nature and good conductivity which allow more efficient diffusion of I- ions and facilitate the transfer of electron in the network.