Hybrid Graphene Quantum Dots@Graphene Foam Nanosheets for Dye‐Sensitized Solar Cell Electrodes

A high-efficiency counter electrode (CE) consisting of zero-dimensional graphene quantum dots (GQDs)@graphene foam nanosheets (GFs) is proposed for dye-sensitized solar cells (DSSCs). In the hybrid CE, the nanometer-sized GQDs with more defect sites at the edges, provide outstanding electrocatalytic activity for the reduction of I3−. The high-quality GFs with high electronic conductivity act as fast electron transportation channels for facilitating the charge injection between the GQDs and the fluorinated tin oxide (FTO) substrate. The DSSC with the optimized hybrid CE exhibits an energy conversion efficiency (η) of 9.59 % with an open-circuit voltage (Voc), short-circuit photocurrent density (Jsc), and fill factor (FF) of 0.75 V, 19.23 mA cm−2, and 66.5 %, respectively.