Anomalous photovoltaic effect in Bi(Ni2/3Ta1/3)O3-PbTiO3 ferroelectric solid solutions

Dense Bi(Ni2/3Ta1/3)O-3-PbTiO3 (BNT-PT) ceramics were prepared by solid-state reaction method. Morphotropic phase boundary between tetragonal and rhombohedral phase was observed around the composition 0.38BNT-0.62PT, at which large photovoltages of 13.2V were obtained under 405nm laser illumination with power density of 200mW/cm(2). By B-site Ni2+ ions doping, the bandgap values of BNT-PT solid solutions were reduced to 2.25 similar to 1.85eV, and the anomalous photovoltaic response was extended from the ultraviolet region to a wavelength of 550nm at the visible light region.