LAUSR

Abstract Driven by their ferroelectric, semiconducting, photonic, etc. properties, the potential of Aurivillius-type oxides of binary Bi4Ti3O12-BiFeO3 system in photovoltaic area is increasingly being studied. In this work, Bi5FeTi3O15 (BFTO-4), Bi6Fe2Ti3O18 (BFTO-5) and Bi7Fe3Ti3O21 (BFTO-6) thin films on soda-lime glass, indium tin oxide (ITO) glass, silicon wafer and Pt/Ti/SiO2/Si substrate were prepared by the chemical solution deposition technique. The photovoltaic responses of the substrate/BFTO-4/Au devices measured by adapting “top-top” or “top-bottom” electrodes were observed. All devices present a similar linear dark J-V curve disjointed to zero point and their photovoltaic properties strongly depended on the substrates and electrode connection forms, arising from self-polarization and interface barrier potential. The optimal photovoltaic effect was observed in the BFTO-4 films on Pt/Ti/SiO2/Si substrate without any poling, with the short circuit current (Jsc) of 18.4 μA/cm2 and open circuit voltage (Voc) of 0.14 V under light illumination, which is attributed to larger polarization and c-axis oriented structure. Furthermore, layer effects on photovoltaic properties of the BFTO-4, BFTO-5 and BFTO-6 films deposited on ITO glass were also investigated. With the increase of layers, the devices exhibit an enhancement of Jsc along with the Voc reduction, due to the intrinsic layered structures with different lattice strains. The switching photocurrent behaviors of the BFTO-4 film by typical ON/OFF light measurements verified the stability and reliability of the photovoltaic effect.