TiO2/Bi5O7I nanocomposite for photoanode of electrochemical cell

Abstract

Bi5O7I is one of the bismuth oxyiodide (BiOI) derivate with bismuth and oxygen-rich contained which can act as semiconductor material. Here, we reported that a successful TiO2/Bi5O7I nanocomposite films fabrication could be carried out by the annealing treatment of TiO2/BiOI films at 450 oC. The prepared films have been applied as the photoanode in photovoltaic devices by adapting the dye-sensitized solar cell (DSSC) model. Our annealed BiOI was Bi5O7I which was proven by the X-Ray diffraction (XRD) patterns of both materials. The usage of Bi5O7I in TiO2/Bi5O7I films could change the optical behavior of films which has been indicated by the decreasing in its band gap energy, extending the absorption wavelength edge of the films. The backscattered scanning electron microscope (SEM) images depicted the incorporation of Bi5O7I in the TiO2-contained films. We designed the photovoltaic device structure as the arrangement: FTO/TiO2/Bi5O7I/Iodine electrolyte/Pt-FTO. Overall, the addition of Bi5O7I could enhance the photovoltaic performance of TiO2/Bi5O7I cells in comparison to the only TiO2 films. The slight enhancement in short-circuit current values over the TiO2/Bi2O3 from the previous report can be the evidence that Bi5O7I is also has the benefit which is not only for photocatalytic reaction, but also the photovoltaic application.