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

Abstract

Herein, the photovoltaic (PV) effect of ferroelectric Bi_0.85La_0.15FeO₃ (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 (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.