Performance enhancement of dye-sensitized solar cells by incorporating graphene sheets of various sizes

Dye-sensitized solar cells (DSSCs) were fabricated using photoanodes made from graphene-TiO2 nanocomposites. The dependence of the size of graphene sheets on the cell performance was investigated. The experimental results indicated that cells loaded with the smaller graphene sheets yielded larger enhancement. The smaller graphene sheets improved the dye adsorption, leading to higher conversion efficiency. The DSSC incorporated with graphene sheets of 184 nm exhibited the largest enhancement in efficiency (∼49%) as compared to the cell without graphene.