Graphene-enhanced three-dimensional structures of MoS 2 nanosheets as a counter electrode for Pt-free efficient dye-sensitized solar cells

Abstract

We developed a 3D MoS2 nanoflakes on graphene aerogel (GA) used as a synthetic template. The resulting MoS2/GA (MG) hybrid possessed 3D nanoscopic layer MoS2 with an abundance of exposed edge sites, in contrast to aggregated MoS2 bulk grown without GA. The MoS2/GA hybrid showed excellent electrical conductivity and catalytic activity as an alternative to platinum counter electrodes in dye-sensitized solar cells (DSSCs) compared to conventional bulk MoS2. The resulting MG-based counter electrodes (CEs) exhibited higher power conversion efficiencies (7.86%) than pure MoS2 (2.2%) and surpassed that of Pt (7.2%). The excellent performance of DSSCs can be ascribed to the abundance of catalytic edge sites and the 3D structure of MoS2 nanoflakes for increased electrolyte/reactant diffusion, and the outstanding electrical coupling to the underlying graphene aerogel. Hence, our results demonstrate that the MG materials deserve further investigation for dye-sensitized solar cells.