One-Pot Controlled Synthesis of Spongelike CuInS2 Microspheres for Efficient Counter Electrode with Graphene Assistance in Dye-Sensitized Solar Cells

Spongelike CuInS2 3D microspheres were synthesized through a solvothermal method employing CuCl, InCl3, and thiourea as Cu, In, and S sources, respectively, and PVP as surfactant. The as-prepared products have regular spherical shapes with diameters of 0.8-3.7 mu m, the spheres consisted of small nanosheets, which are composed of small nanoparticles. As an important solar cell material, its photovoltaic property was also tested and the results showed a solar energy conversion efficiency of 3.31%. With the help of reduced graphene, its conversion efficiency could be further increased to 6.18%. Compared with conventional Pt material used in counter electrodes of solar cells, this new material has an advantages of low-cost, facile synthesis and high efficiency with graphene assistance.