A controllable photoresponse and photovoltaic performance in Bi4Ti3O12 ferroelectric thin films

Polycrystalline Bi4Ti3O12(BIT) thin films were prepared on the fluorine-doped tin oxide glass substrates by a simple sol-gel method. Structural, ferroelectric and optical properties as well as photovoltaic properties and photocurrent responses of the BIT films in different conditions were investigated. The unpoled BIT film revealed an obvious photovoltaic effect with J(sc) of about 0.18 mu A/cm(2) and V-oc of about 0.02 V. The photoresponse of the film was increased by applying positive biases, while decreased by negative biases. On the other hand, its photoresponse was markedly increased to almost three times of that of the unpoled film through negative poling. Positive poling not only decreased the photocurrent, but also reversed the photocurrent direction. The wide tunability of photovoltaic performance and photoresponse proved BIT to be a promising alternative material for ferroelectric photovoltaics for applications in ferroelectric optoelectronic and energy fields. (C) 2016 Elsevier B.V. All rights reserved.