Photoelectrochemical Performance Observed in Mn-Doped BiFeO(3) Heterostructured Thin Films

Pure BiFeO(3) and heterostructured BiFeO(3)/BiFe(0.95)Mn(0.05)O(3) (5% Mn-doped BiFeO(3)) thin films have been prepared by a chemical deposition method. The band structures and photosensitive properties of these films have been investigated elaborately. Pure BiFeO(3) films showed stable and strong response to photo illumination (open circuit potential kept −0.18 V, short circuit photocurrent density was −0.023 mA·cm(−2)). By Mn doping, the energy band positions shifted, resulting in a smaller band gap of BiFe(0.95)Mn(0.05)O(3) layer and an internal field being built in the BiFeO(3)/BiFe(0.95)Mn(0.05)O(3) interface. BiFeO(3)/BiFe(0.95)Mn(0.05)O(3) and BiFe(0.95)Mn(0.05)O(3) thin films demonstrated poor photo activity compared with pure BiFeO(3) films, which can be explained by the fact that Mn doping brought in a large amount of defects in the BiFe(0.95)Mn(0.05)O(3) layers, causing higher carrier combination and correspondingly suppressing the photo response, and this negative influence was more considerable than the positive effects provided by the band modulation.