Hexagonal FeS nanosheets with high-energy (001) facets: Counter electrode materials superior to platinum for dye-sensitized solar cells
FeS nanosheets, high-energy facets, counter electrode, first-principles calculation, catalytic reduction
The catalytic activity of materials is highly dependent on their composition andsurface structure, especially the density of low-coordinated surface atoms. Inthis work, we have prepared two-dimensional hexagonal FeS with high-energy(001) facets (FeS-HE-001) via a solution-phase chemical method. Nanosheets(NSs) with exposed high-energy planes usually possess better reaction activity,so FeS-HE-001 was used as a counter electrode (CE) material for dye-sensitizedsolar cells (DSSCs). FeS-HE-001 achieved an average power conversion efficiency(PCE) of 8.88% (with the PCE of champion cells being 9.10%), which was almost1.15 times higher than that of the Pt-based DSSCs (7.73%) measured in parallel.Cyclic voltammetry and Tafel polarization measurements revealed the excellentelectrocatalytic activities of FeS-HE-001 towards the I3–/I– redox reaction. Thiscan be attributed to the promotion of photoelectron transfer, which was measuredby electrochemical impedance spectroscopy and scanning Kelvin probe, and thestrong I3– adsorption and reduction activities, which were investigated usingfirst-principles calculations. The presence of high-energy (001) facets in the NSswas an important factor for improving the catalytic reduction of I3–. We believethat our method is a promising way for the design and synthesis of advanced CEmaterials for energy harvesting.
Tsinghua University Press
Xiuwen Wang,Ying Xie,Buhe Bateer,Kai Pan,Yangtao Zhou,Yi Zhang,Guofeng Wang,Wei Zhou,Honggang Fu, Hexagonal FeS nanosheets with high-energy (001) facets: Counter electrode materials superior to platinum for dye-sensitized solar cells. NanoRes.2016, 9(10): 2862–2874