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.