Two-Dimensional Molecular Ferroelectric Thin Films for Polarization-Driven Tunable Photovoltaic Devices with High Photocurrent Density

The photovoltaic effect driven by ferroelectric polarization shows great application potential in photovoltaic devices. Two-dimensional (2D) Ruddlesden–Popper perovskite molecular ferroelectric materials, which combine adjustable structure, polarization, and low band gap properties, occupy a promising position in this field. However, most of the studies on molecular ferroelectrics reported in the literature focus on single crystals, while there are few reports on thin film devices. In this paper, 2D EA2MA2Pb3Br10 (EA = ethylammonium, MA = methylammonium) molecular ferroelectric materials are used to prepare molecular ferroelectric photovoltaic devices, and polarization-driven controllable photovoltaic devices are successfully realized. Under the irradiation of standard sunlight, the device exhibits a significant photovoltaic effect, and its short-circuit current density reaches the order of mA/cm2, which is much higher than that of ordinary inorganic ferroelectrics. In addition, by applying an external electric field, the photovoltaic performance of the device can be significantly improved, and multilevel regulation can be achieved. The results provide a viable method for developing polarization-driven tunable photovoltaic devices based on 2D molecular ferroelectrics.