Polyoxometalates-doped metallic 1T-MoS2 as a high efficiency counter electrode material for solar cells

1T-MoS2 has the potential as a counter electrode material for dye-sensitized solar cells (DSSCs) due to its unique energy band electronic structure that gives it metallic properties and a conductivity nearly 10(7) times higher than that of the common 2H-MoS2. However, the pure phase 1 T-MoS2 has the disadvantages of low catalytic performance and poor thermal stability. Polyoxometalates (POMs) are a type of inorganic polymetallic oxygen clusters, which have lots of exposed redox sites and good structural stability. In this article, three different POMs (CoMo6, NiMo6, and FeMo6) have been dispersed and loaded into 1 T-MoS2, which led to a synergistic effect between highly redox-active POMs and highly conductive 1 T-MoS2. Among the three different POMs/MoS2, the DSSCs prepared with FeMo6/MoS2 as the counter electrode material has the optimal Power Conversion Efficiency (PCE), which reaches 6.36% at a doping level of 0.5 mg mL(-1) of FeMo6, which is higher than that of Pt (5.94%), and it has a good long-term stability. This work offers a valuable method for the design of composite materials for the reduction of I-3(-), and the resulting counter electrode, with its excellent performance and low cost, promotes further industrialization of DSSCs.