Plasmonic-enhanced photovoltaic output in bismuth ferrite films

Recently, the ferroelectric photovoltaic effect of BiFeO3 has attracted much attention due to its above-bandgap photovoltage and switchable photocurrent. However, the very low photocurrent density hinders its practical application. In this paper, elaborate photovoltaic heterostructures were constructed by BiFe0.9375Ti0.0625O3 (BFTiO) film and Au nanoparticles layer. The results and analysis demonstrate that these heterostructures exhibit a huge enhancement in photocurrent density. A possible mechanism for the enhanced photocurrent density is proposed herein based on the Local Surface Plasmon Resonance (LSPR) effect. First, the incident light reaching the Au nanoparticles is amplified by the LSPR effect and reflected into the BFTiO film, thus improving its light absorption. Second, the photogenerated electrons in the vicinity of the BFTiO-Au interface are accelerated by the enhanced electromagnetic field caused by the LSPR effect, thereby promoting the separation efficiency of the photogenerated carriers. Consequently, the LSPR effect significantly increases the photocurrent density of the BFTiO film.