Optimization of overall device structure significantly boosted power conversion efficiency of bismuth ferrite-based ferroelectric photovoltaic cells for commercial applications

Although ferroelectric photovoltaic effect of BiFeO₃ has emerged as a hotspot in solar cell research, its low power conversion efficiency (PCE) has become major roadblocks to its commercial use. An innovative device of FTO/Au-NPs/TiO₂/BTFCO-g/NiO/Au was fabricated herein on the basis of (Tm, Co)-gradient-doped BiFeO₃ (BTFCO-g) thin film, where three built-in electric fields are created and coupled with one another to enhance the photocurrent density. Furthermore, Localized Surface Plasmon Resonance (LSPR) effect of Au nanoparticles (Au-NPs) greatly enhances photogenerated carrier's separation efficiency and secondary light absorption in BTFCO-g film, which further enhance the photocurrent density. Especially, introduction of carrier transport layers (TiO₂ and NiO) increases both the photovoltage and photocurrent. Such overall device structure optimization boosts device's PCE to a staggering 16%. This significant development is anticipated to hasten the commercial adoption of ferroelectric photovoltaic devices as a novel form of solar cell.