Electric polarization tune enhanced photoelectrochemical performance of visible light active ferroelectric Bi0.5Na0.5TiO3 nanostructure photoanode

Significantly enhanced photoelectrochemical (PEC) performance of the visible light active photoanodes of ferroelectric Bi0.5Na0.5TiO3 nanostructure has been demonstrated by tuning the electrical polarization of the film. The photocurrent density of unpoled Bi0.5Na0.5TiO3 photoanode increases from 0.48 mA cm(-2) at 1 V with respect to Ag/AgCl to 1.21 mA cm(-2) after negative poling, whereas it decreases to 0.18 mA cm(-2) after positive poling. The incident photon-to-current conversion efficiency (IPCE) of the nanostructure photoanodes has been observed to vary from 5% to 28% just by changing the direction of electric polarization. The change in the PEC performance and enhancement in the IPCE value after switching the polarization state of Bi0.5Na0.5TiO3 photoanodes have been attributed to the modification in the band bending at the interface of semiconductor electrode/electrolyte, leading to facilitate the increment in photogenerated charge transfer efficiency. The modulation in the band bending and variation in the charge transfer method after switching the polarization state are confirmed by Mott Schottky (M-S) and electrochemical impedance spectroscopy (EIS) measurements. Our work provides a new visible light active ferroelectric nanostructure material for efficient visible light active photo electrochemical performance. (c) 2021 Elsevier Ltd. All rights reserved.