Performance of FTO-free conductive graphene-based counter electrodes for dye-sensitized solar cells

The attractiveness of graphene arises from its low cost, transparency, high electrical conductivity, chemical robustness, and flexibility, as opposed to the rising cost and brittleness of FTO. In particular, graphene is emerging as a possible substitute for FTO in flexible displays, touch screens, and solar cells. The main goal of our work is to develop new conductive oxide free graphene-based counter electrodes for dye sensitized solar cells (DSSCs). Graphene nanoplates are modified by silane coupling agent to introduce vinyl groups, and then mixed with polyurethane adhesive and cast on glass substrate. The film is irradiated by UV source and heat treated under Ar/H2. A network graphene film is formed and tightly bonded on glass substrate with enhanced electrical conductivity. The structure of network graphene is investigated by XPS, TGA and SEM. The DSSCs with network graphene counter electrode exhibit power conversion efficiencies of 9.33%, much better than those with FTO electrodes (4.05%).