Photoelectrochemical Performance Observed in Mn-Doped BiFeO₃ Heterostructured Thin Films

Hao-Min Xu; Huanchun Wang; Ji Shi; Yuanhua Lin; Cewen Nan

doi:10.3390/nano6110215

Photoelectrochemical Performance Observed in Mn-Doped BiFeO₃ Heterostructured Thin Films

Nanomaterials (Basel). 2016 Nov 16;6(11):215. doi: 10.3390/nano6110215.

Authors

Hao-Min Xu¹, Huanchun Wang^{2

3}, Ji Shi⁴, Yuanhua Lin⁵, Cewen Nan⁶

Affiliations

¹ State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China. xuhm13@mails.tsinghua.edu.cn.
² State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China. wanghc12@mails.tsinghua.edu.cn.
³ High-Tech Institute of Xi'an, Xi'an 780025, China. wanghc12@mails.tsinghua.edu.cn.
⁴ Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8552, Japan.
⁵ State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China. linyh@mail.tsinghua.edu.cn.
⁶ State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China. cwnan@mail.tsinghua.edu.cn.

Abstract

Pure BiFeO₃ and heterostructured BiFeO₃/BiFe_0.95Mn_0.05O₃ (5% Mn-doped BiFeO₃) thin films have been prepared by a chemical deposition method. The band structures and photosensitive properties of these films have been investigated elaborately. Pure BiFeO₃ 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_0.95Mn_0.05O₃ layer and an internal field being built in the BiFeO₃/BiFe_0.95Mn_0.05O₃ interface. BiFeO₃/BiFe_0.95Mn_0.05O₃ and BiFe_0.95Mn_0.05O₃ thin films demonstrated poor photo activity compared with pure BiFeO₃ films, which can be explained by the fact that Mn doping brought in a large amount of defects in the BiFe_0.95Mn_0.05O₃ 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.

Keywords: Mn-doped BiFeO3 films; heterostructure; photocatalysis; photoelectrochemical; solar energy conversion.