Facile Synthesis of VxA1-x(x=0-1, A = C, O) Multiphase Composites Derived from Polyoxovanadate Precursors by Pyrolysis along a Temperature Gradient as Pt-free Counter Electrodes for High-Efficient Dye-Sensitized Solar Cells

Replacing precious Pt-based counter electrodes (CEs) with a low-cost and high-performance Pt-free catalyst of CEs is still in urgent need to decrease the fabrication cost of dye-sensitized solar cells (DSSCs). Herein, the elements V and A (A = C, O) of the final state of the target materials are prefabricated in an organic complex precursor by bonding, and then, the precursor was directly processed to prepare V(x)A(1-x)(x = 0-1, A = C, O) multiphase CE catalysts by pyrolysis along the temperature gradient under N-2 flow, which further served as catalytic materials of CEs for the encapsulation of DSSCs. The precursors were obtained utilizing polyoxovanadate (NH4)(2)V6O16 as a metal source and glucose as a carbon source via a facile hydrothermal method. Power conversion efficiencies of 5.38, 6.29, 6.60, 6.82, and 6.23% were obtained from the five different V(x)A(1-x)(x = 0-1, A = C, O) multiphase CE catalysts as CEs to reduce iodide/triiodide in DSSCs, which were prepared at pyrolysis temperatures of 600, 700, 800, 900, and 1000 degrees C, respectively. The enhanced performance of V(x)A(1-x) materials can be attributed to the more catalytic active site number and the high conductivity, which is due to the higher specific surface area provided by the pyrolysis and carbonization of glucose and the activation and modification of materials at high temperature and N-doping. The impressive finding in this work indicates that the V(x)A(1-x) composite can be considered as a promising candidate for low-cost and high-efficient CEs in the fabrication of DSSCs.

Automated summary

The V(x)A(1-x) multiphase CE catalysts prepared via pyrolysis under temperature gradient demonstrated enhanced catalytic activity and high conductivity for the reduction of iodide/triiodide in DSSCs. The materials showed promise as low-cost and efficient CEs due to increased catalytic active sites and conductivity achieved through high temperature pyrolysis and carbonization.