Enhanced photovoltaic efficiency and persisted photoresponse switchability in LaVO3/Pb(Zr0.2Ti0.8)O3 perovskite heterostructures

Abstract

For ferroelectric photovoltaics, it is challenging to enhance the power conversion efficiency (PCE) without sacrificing the photoresponse switchability. Here, we demonstrate that enhanced PCE and good photoresponse switchability can be simultaneously achieved in perovskite heterostructures comprising narrow-gap semiconductor LaVO₃ (LVO) and ferroelectric Pb(Zr_0.2Ti_0.8)O₃ (PZT). The LVO(24 nm)/PZT(120 nm) based device exhibits a ∼5-fold enhancement in PCE compared with the PZT-only based device, which is attributed to the enhanced absorption from the LVO layer and the built-in field at the LVO/PZT interface facilitating the separation of photo-generated e–h pairs. In addition, the switched photovoltage of the LVO/PZT based device is above 1 V, which is as large as that of the PZT-only based device. This persisted photoresponse switchability is obtained because the polarization can be fully switched in the LVO/PZT based devices when the LVO thickness is less than 24 nm. Our finding therefore provides a promising route for the development of high-efficiency and highly switchable ferroelectric photovoltaic devices.