Design and fabrication of layered TiO2/rGO composited photoanode and its photovoltaic performance regulation for dye-sensitized solar cells

Abstract

To improve the photovoltaic performance of the traditional TiO2 photoanode for dye-sensitized solar cells (DSSCs), a series of layered TiO2/rGO composited DSSCs photoanode was assembled by changing the morphologies of the TiO2 and introducing reduced graphene oxide (rGO) into different areas of the photoanode films. Firstly, TiO2 nanoflowers (TiO2-NFs), TiO2 nanorods (TiO2-NRs) were prepared employing the hydrothermal method and used as photoanode materials to explore the synergistic effect of TiO2 with different morphologies in layered photoanode. Then, TiO2-NFs/rGO composited photoanode (TNF/rGO) were fabricated to research the mechanism of rGO on improving electron transmission in the layered photoanode. The effect of adding rGO at different parts of the layered photoanode on the performance of DSSCs was also investigated. Attributing to the enhancement of light absorption and charge transfer, a champion power conversion efficiency (η) of 9.21 % (Jsc = 23.36 mA cm−2, Voc = 0.74 V, FF = 0.53) was achieved with the layered TiO2/rGO composited photoanode containing two consecutive layers of TiO2-NFs/rGO and P25/rGO, which exhibited an 82.01 % increase than traditional TiO2 (pure P25) photoanode (η = 5.06 %, Jsc = 12.09 mA cm−2, Voc = 0.73 V, FF = 0.58). It is an effective way to design and fabrication of layered TiO2/rGO composited photoanode to regulate the photovoltaic performance of traditional TiO2 photoanode for DSSCs based on the synergistic effect of its multi-layer structure, TiO2 morphologies and introduction of rGO.