Photovoltaic Effect Induced by Self-Polarization in BiFeO₃ Films

Abstract

In this work, a significant visible-light photovoltaic effect is obtained under the influence of a built-in electric field in BiFeO 3 thin films. The photocurrent density, open-circuit voltage, and short-circuit current of the films are investigated systematically. For cells, the open-circuit voltage increases from 0.08 to 0.26 V after irradiation with light with a wavelength of 550 nm at a power density of 0.18 mW/nm. The photocurrent density at 550 nm reaches 1.8 × 10 −7 A/cm 2 , which is two orders higher compared to that of the dark state. The significant increase in these parameters is closely related to the separation and transport of photogenerated carriers driven by the built-in electric field. From the results, it is expected that this work can provide a method for improving the photoelectric performance of photovoltaic devices based on ferroelectric materials.

Ferroelectric Modulation of Surface Electronic States in BaTiO3 for Enhanced Hydrogen Evolution Activity

“…Ferroelectric perovskites have also been an interesting class of nanomaterials for photocatalysis, since their internal electric field can be used to enhance electron–hole separation. ,− As a recent example, improved photocatalytic oxygen evolution activity has been reported using both bare ferroelectric (e.g., BaTiO 3 , BiFeO 3 , ) films and ferroelectric-supported catalysts, such as RuO 2 /BiFeO 3 . In these studies the heterostructure was used as a photoanode, where ferroelectric polarization enhanced the accumulation of photogenerated holes near the surface to facilitate water oxidation.…”

A self-powered flexible UV-visible photodetector with high photosensitivity based on BiFeO3/XTiO3 (Sr, Zn, Pb) multilayer films

“…The E b of BFO film is closely related to the domain orientation of the ferroelectric BFO layer. 31 Fig. 3(a–c) shows the domain orientation diagram of BFO/XT multilayer films observed using a piezoelectric force microscope (PFM).…”

“…The energy band of BFO films tilted under the action of the LNO buffer layer and E b , which has been confirmed in our previous work. 31 In addition, XT is the UV absorption layer that enhances the absorption of UV light energy and increases photogenerated carriers; the band gap of XT thin films was summarized from references, and the values are ∼3.4, ∼3.08, and ∼3.2 eV for ST, ZT, and PT, respectively. The band gap of ZT is the narrowest, so the highest photon energy is absorbed by BFO/ZT multilayers.…”

“…In previous studies, we have obtained a stable photovoltaic effect in self-polarized BFO films with the LaNiO 3 (LNO) buffer layer, especially observed under an obvious switchable photocurrent under zero bias voltage. 31 The LNO buffer layer is beneficial to the crystallization and preferred orientation of the BFO layer, and stress is generated between the LNO and BFO layers due to the lattice mismatch. 61,62 In addition, the built-in electric field in the BFO layer mainly originates from the Bi volatilization and defects, but the defects are unstable in the BFO layer.…”

Improved Self-Powered Photodetection of Ferroelectric PbZr0.52Ti0.48O3 Thin Films via Interfacial Engineering

“…7 However, the fabrication of such devices has involved complex fabrication processes. In contrast, ferroelectric semiconductors, such as BiFeO 3 (BFO), 8,9 PbZr 0.52 Ti 0.48 O 3 (PZT), 10,11 and BaTiO 3 (BTO), 12,13 featured with strong spontaneous electric polarization have been proposed to fabricate self-powered PDs. It is worth noting that the electric polarization can provide a strong internal electric field (i.e., depolarization electric field), and it can be further either enhanced or reversed by the application of an external electric field.…”