Synthesis Of Carbon Sphere And Molybdenum Carbide Sphere And Their Application In Dye-sensitized Solar Cells

Counter electrode(CE) is an important part of the dye-sensitized solar cells(DSCs), which not only plays a crucial role of catalyst, but also furnishes sites for redox reaction. Generally, platinum is used as CE catalytic materials. However, there are also many disadvantages, which hinder the application of Pt CE. Here, we introduce some spherical catalytic materials including carbon spheres and molybdenum carbide sphere.Hydrothermal method is employed to prepare solid carbon sphere(denoted as SCS), hollow carbon sphere(denoted as HCS) and open-ended carbon sphere(denoted as OCS). The designed OCS shows higher electrocatalytic activity than the conventional solid and hollow carbon sphere as CE catalyst for the regeneration of both iodide(I3-/I-) and sulfide(T2/T-) redox shuttles in DSCs. The high catalytic activity of OCS benefits from the sufficient contact between the redox shuttle with the external and internal surfaces of OCS because an open end exists on the surface of OCS, which provide a diffusion channel for the electrolyte into the inner of OCS. This strategy for designing open-ended structure is highly important for the fields of drug delivery, nanodevice, and adsorption, but not confined to catalysis. Molybdenum carbide sphere(denoted as Mo2C-MSs) are synthesized and shows remarkable catalytic activity for regeneration of both I3-/I- and T2/T- redox shuttles in DSCs. For the iodide redox shuttles, the DSCs using Mo2C-MSs as the CE shows a high power conversion efficiency of 7.28%, which approach to the DSCs using a conventional Pt CE(7.85%). For the sulfide redox shuttles, the Mo2C-DSCs shows power conversion efficiency of 5.47 %, which is much higher than the Pt-DSCs(3.91%).In conclusion, carbon sphere and Molybdenum carbide sphere expand the range of CE catalytic materials to some extent and reduce the cost of production, which promotes the process of industrialization.