Preparation And Ta Doping Effect On The PEC Performance Of Hematite Thin Films

The efficient use of solar energy has become a research focus in new energy field. Hematite with narrow band gap shows a good photoelectrochemical response for both ultraviolet light and visible light.hi this work, we present three different approach for preparing undoped and Ta doped hematite and the effect of doping on PEC performance were investigated, the morphology, surface state and electronic structure of undoped and Ta doped hematite dot-matrix film to assess the mechanisms by which the dopants influence photoanodes performance.The hematite dot-matrix films with better repeatability and uniformity fabricated by a solution dispenser can provide more reliable data. Ta plays a role in preventing the hematite films from dissolving into the acid aqueous solution during the hydrothermal process. Compared with undoped hematite, hematite doped with2.0%Ta showed a great10-fold enhancement in photocurrent density.The crystal phase of the hematite prepared by hydrothermal method with preferred orientation in the [110] direction is thought to be related to the enhanced photocurrent. The XPS results indicate that the Ta5+dopants are substitutionary incorporated at the Fe3+sites in the hematite lattice. The calculated value of Ta/Fe (by atomic basis) from XPS spectra is close to the molar ratio in the precursor solution. Mott-Schottky results suggest that it was the increased carriers that contributed to the significant enhanced photocurrent. Raman spectra results indicate that the introduction of Ta lead to the increased surface trapping states can result in the enhanced recombination and then downside to photocurrent.