Pure inorganic D–A type polyoxometalate/reduced graphene oxide nanocomposite for the photoanode of dye-sensitized solar cells

Abstract

A pure inorganic donor–acceptor (D–A) type polyoxometalate K₆H₄[α-SiW₉O₃₇Co₃(H₂O)₃]·17H₂O (SiW₉Co₃)/reduced graphene oxide (RGO) nanocomposite was employed to dye-sensitized solar cells (DSSCs) for the first time, building up a wide spectrum for the photoanode of a DSSC. Raman, XRD, TEM, and EDS have proved that SiW₉Co₃ was loaded on RGO, and then the SiW₉Co₃/RGO doped nanocomposite in P25 was applied to be the photoanode of the DSSCs. In this paper the performance of SiW₉Co₃/RGO-3@P25 is the best. The J_sc of pure P25 is 13.74 mA cm⁻², V_oc is 0.679 V, FF is 0.598 and η is 5.37%, while the J_sc of SiW₉Co₃/RGO-3@P25 is 17.5 mA cm⁻², V_oc is 0.705 V, FF is 0.558 and η is enhanced to 6.88%, which is 28.05% higher than for a pure P25-based cell in a DSSC. OCVD indicates that SiW₉Co₃/RGO can delay the electron–hole recombination. In a Bode plot the electron lifetimes of SiW₉Co₃/RGO-3@P25 and P25 are 4.86 ms and 3.81 ms respectively, which also further clarifies that the SiW₉Co₃/RGO doped nanocomposite can extend the lifetime of electrons and also plays an important role in the photoanode of the DSSCs. This result is beneficial to the application of DSSCs in future industry.