Optical and electrical properties of ferroelectric BaxBi0.5-0.5xAg0.05-0.5xNa0.45Ti1-xNi0.5xNb0.5xO3 semiconductor ceramics

•Dielectric/ferroelectric properties of BANT-xBNN ceramics were investigated.•Perfect ferroelectricity and low optical band gap ~2.3 eV.•The improved Jsc and Voc, poled at 2.0 kV, is 2.79 nA/cm2 and 0.54 V, respectively. Perovskite-oxide ferroelectric semiconductors were widely concerned in photovoltaic applications due to its excellent optical absorption and thermal stability. In this work, BaxBi0.5-0.5xAg0.05-0.5xNa0.45Ti1-xNi0.5xNb0.5xO3 ceramics (abbreviation as BANT-xBNN) were successfully prepared by using a solid-state reaction method. All the ceramics illustrate perfect ferroelectric behavior. The addition of BaNi0.5Nb0.5O3 can substantially reduce the band gap of Ag doped Bi0.5Na0.5TiO3 material to ~2.3 eV. The short-circuit current (Jsc) and the open-circuit voltaic (Voc) of the selected BANT-0.04BNN ceramic poled at 2.0 kV, is 2.79 nA/cm2 and 0.54 V, respectively. The novel BANT-xBNN system has broad application prospects for ferroelectric photovoltaic devices.