Ce–Co-doped BiFeO₃ multiferroic for optoelectronic and photovoltaic applications

The Ce-Co-doped BiFeO₃ multiferroic, Bi_1-xCe_xFe_1-xCo_xO₃ (x=0.00, 0.01, 0.03, and 0.05), has been prepared by a sol-gel auto-combustion method and analyzed through Raman spectroscopy, photoluminescence, and UV-visible spectroscopy. We have observed an anomalous intensity of the second-order Raman mode at~1260 cm^-1 in pure BFO and suppressed intensity in doped samples, which indicates the presence of spin two-phonon coupling in these samples. The photoluminescence spectra show reduction in the intensity of emission with the increasing dopant concentration, which indicates the high charge separation efficiency. A sharp absorption with three charge transfer (C-T) and two d-d transitions are shown by UV-visible spectra in the visible region. The band gap of BiFeO₃ (BFO) is decreasing with increasing dopant concentrations and the materials are suitable for photovoltaic applications.