Microstructures and Photovoltaic Properties of TiO2/BiFeO3 Core-Shell Nanowire Arrays

To address the current problem of low photoelectric conversion efficiency of BiFeO3 (BFO)-based photovoltaic (PV) devices, a TiO2/BFO core-shell nanowire array structure was constructed in this study based on the characteristics of excellent light reflection, stronger light-trapping effect, large specific surface area, fast transport rate of photogenerated carriers, and good energy band matching relationship. The TiO2/BFO core-shell nanowire arrays were prepared by the hydrothermal and sol-gel methods. The experimental results show that the light absorption performance of the TiO2/BFO core-shell nanowire arrays is significantly enhanced compared with the previously reported BFO-based ferroelectric photovoltaic (FEPV) films, and the conversion efficiency has significantly improved to 0.1177%. The intrinsic mechanism of PV enhancement of the designed TiO2/BFO core-shell nanowire array structure was illustrated by combining optical absorption, carrier lifetime, and energy band structure. This study further demonstrates the potential applications of transport material/ferroelectric material core-shell nanowire array structures in PV devices.