A New Aspect for Band Gap Energy of Graphene-Mg2CuSnCoO6-Gallic Acid as a Counter Electrode for Enhancing Dye-Sensitized Solar Cell Performance.

To develop counter electrodes (CEs) for dye-sensitized solar cells (DSSCs), band gap energy of quaternary semiconductor materials is of great interest. In the present study, a novel graphene sheet based on Mg2CuSnCoO6-Gallic acid nanomaterials (G/MCS@Gallic) was modified with a new Joule heating method, and a laser was applied for measuring band gap energy. Synergistic effect between graphene and Mg2CuSnCoO6-Gallic ensured excellent electron transport through the electrode and low band gap energy. The large surface area of the hybrid graphene materials rivaled the catalytic capability for iodide reduction. DSSCs achieved a maximum photoelectric conversion efficiency of 13.30% based on the 10% G/MCS@Gallic CE, which was higher than the platinum conversion efficiency. Thus, G/MCS@Gallic provides a novel, inexpensive, high-performance, and flexible cathode for solar cell applications.