MnO2 nanotubes with graphene-assistance as low-cost counter-electrode materials in dye-sensitized solar cells

Abstract

MnO₂ nanotubes were synthesized via hydrothermal conditions. We investigated their catalytic activities with a counter electrode (CE) in DSSCs by photocurrent–voltage (J–V) curves and measured conversion efficiency. To enhance their power conversion efficiency (PCE), different amounts of reduced graphene were added by simple physical mixing. With the addition of 6 wt% reduced graphene (rGO), the short-circuit current density, open-circuit voltage, and fill factor (FF) were J_sc = 15.97 mA, V_oc = 0.71 V, and FF = 0.51. Furthermore, the conversion efficiency achieved 5.77%, which was slightly better than the commercial Pt CE (PCE = 5.40%). Compared to the traditional Pt CE of DSSCs, this material has the advantages of low cost, simple synthesis, and high conversion efficiency with graphene assistance.