Synthesis of hemin functionalized graphene and its application as a counter electrode in dye-sensitized solar cells

This work reports a facile and rapid method assisted by microwave irradiation for the synthesis of hemin functionalized reduced graphene oxide (hemin-RGO) materials. Our investigation confirmed that the hemin molecules were covalently grafted to the surface of graphene by the amidation reaction of the NH2 groups on the edges of ethylenediamine functionalized graphene oxide with the COOH groups of hemin. Hemin-RGO exhibits a homogeneous dispersion in water, dimethylformamide, and acetone after more than one month, indicating that hemin can effectively improve the dispersion and solubility of RGO in the solvent. Hemin-RGO was used as a counter electrode in dye-sensitized solar cells and exhibited preferable electrocatalytic activity for I3-to I-reduction compared with RGO. © 2011 Elsevier B.V. All rights reserved.