The
intrinsic electric field in piezoelectric materials strongly
controls the recombination dynamics, and choosing a specific piezoelectric
material in designing a photocatalyst is of great interest. Herein,
uniform BiOBr single-crystal micro–nanosheets with 2–8
μm side length and 100–300 nm thickness were suitably
prepared using a hydrothermal method after optimizing the fabrication
parameters. A near single-domain structure with reversible polarization
switching was detected along with a typical butterfly-shape piezoelectric
hysteresis loop, showing over 150 pm displacement under a ∼37
V bias voltage. Photoelectric characterization displayed almost a
three times difference for the photoelectric anisotropy along and
perpendicular to the plane, whereas the photoelectrochemical measurement
indicated a low charge transfer resistance and a correspondingly efficient
photoelectrochemical response under 365 nm laser, which are attributed
to the significant increase in surface potential observed using Kelvin
probe force microscopy and the potential internal field related to
the piezoelectricity.