Enhanced photovoltaic effects in A-site samarium doped BiFeO3 ceramics: The roles of domain structure and electronic state

This work reports enhanced photovoltaic (PV) responses of (Bi(1-x)Sin(x))FeO3 (x=0.0, 0.05, 0.10) ceramics (BF100xSm) with ITO film under near -ultraviolet irradiation (lambda = 405 nm). The ceramics were characterized by micro-Raman scattering, high-resolution transmission electron microscopy, and synchrotron X-ray absorption spectroscopy (XAS). A rhombohedral R3c symmetry with tilted FeO6 octahedra has been confirmed. The Fe K -edge absorption spectra reveal a slight shift toward higher energy as A -site Sm3* substitution increases. The oxygen K -edge XAS reveals an enhancement of hybridization between the O 2p and unoccupied Fe 3d states due to Sm doping. The optical band gaps are in the range of 2.15-2.24 eV. The maximal PV power-conversion and external quantum efficiencies respectively reach 037% and 4.1% in the ITO/BFO5Sm/Au heterostructure. The PV responses can be described quantitatively by a p -n -junction like model. The domain structures and hybridization between the O 2p and Fe 3d states play important roles for the PV responses. (C) 2015 Elsevier Ltd. All rights reserved.