Understanding the impact of Bi stoichiometry towards optimised BiFeO photocathodes: structure, morphology, defects and ferroelectricity.

BiFeO thin films have been widely studied for photoelectrochemical water splitting applications because of its narrow bandgap and good ferroelectricity which can promote the separation of photo-generated charges. Bismuth is well known as a volatile element and excess bismuth is usually added into the precursor to compensate the loss of bismuth during heat treatment, but the amount of excess bismuth required and how excess bismuth will affect PEC performance have not been clearly studied. Herein, self-doped Bi FeO thin films are prepared simple chemical solution deposition method with excess bismuth from 0-30% in the precursor.