Photovoltaic enhancement by Au surface-plasmon effect for La doped BiFeO3 films

Herein, the photovoltaic (PV) effect of ferroelectric Bi0.85La0.15FeO3 (BLFO) films fabricated through a sol-gel method is investigated. The ferroelectric properties of the BLFO films improve compared to the undoped BiFeO3 films. The application of Au nanoparticles (AuNPs) increases the open circuit voltage (VOC) and short circuit current density (JSC) from 0.2 V to 0.3 V and 5.3 mA cm(-2) to 18.5 mA 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.