Piezo-photoferroelectric response in bismuth-modified KNBNBiNO

Abstract The incorporation of bismuth (5% mol) into the B-site of the complex perovskite structure that gives rise to the (K 0.49 Na 0.49 Ba 0.02 )(Ni 0.01 Bi 0.05 Nb 0.94 )O 2.945 (named KNBNBiNO) system increases the concentration of oxygen vacancies and results in higher polarization values. The out-of-plane and in-plane polarized ferroelectric domains were confirmed by Piezoresponse Force Microscopy (PFM). The effective piezoelectric coefficient, d eff , measured by PFM, changed from 11 pm/V in dark to 69 pm/V under sustained white light illumination. The influence of the photoferroelectric effect on the piezoelectric properties of the present system, is described. Graphical abstract