Photovoltaic enhancement by Au surface-plasmon effect for La doped BiFeO 3 films

Herein, the photovoltaic (PV) effect of ferroelectric Bi 0.85 La 0.15 FeO 3 (BLFO) films fabricated through a sol–gel method is investigated. The ferroelectric properties of the BLFO films improve compared to the undoped BiFeO 3 films. The application of Au nanoparticles (AuNPs) increases the open circuit voltage ( V OC ) and short circuit current density ( J SC ) from 0.2 V to 0.3 V and 5.3 μA cm −2 to 18.5 μA cm −2 , respectively, which could be attributed to Au surface-plasmon effects. The PV output for the BLFO film can be modulated after applying external poling voltages. Considering the ferroelectric polarization and plasmonic effects, a plausible theoretical model is constructed to depict the physical mechanism of PV enhancement for the BLFO film in detail. This work not only presents a new approach to improve the PV effect of ferroelectric films but also provides important insights into the PV mechanism of ferroelectric films.