Enhanced Photovoltaic Performances of La-Doped Bismuth Ferrite/Zinc Oxide Heterojunction by Coupling Piezo-Phototronic Effect and Ferroelectricity

Abstract

Ferroelectric materials have drawn widespread attention due to their switchable spontaneous polarization and anomalous photovoltaic effect. The coupling between ferroelectricity and the piezo-phototronic effect may lead to the design of distinctive photoelectric devices with multifunctional features. Here, we report an enhancement of the photovoltaic performances in the ferroelectric p-type La-doped bismuth ferrite film (BLFO)/n-type zinc oxide (ZnO) nanowire array heterojunction by rationally coupling the strain-induced piezoelectricity in ZnO nanowires and the ferroelectricity in BLFO. Under a compressive strain of −2.3% and a 10 V upward poling of the BLFO, the open-circuit voltage (V OC) and short-circuit current density (J SC) of the device increase by 8.4% and 54.7%, respectively. Meanwhile, the rise (/decay) time is modulated from 153.7 (/108.8) to 61.28 (/74.86) ms. Systematical band diagram analysis reveals that the promotion of photogenerated carriers and boost of the photovoltaic performances of the device can be attributed to the modulated carrier transport behaviors at the BLFO/ZnO interface and the superposed driving forces arising from the adding up of the piezoelectric potential and ferroelectric polarization. In addition, COMSOL simulation results of piezopotential distribution in ZnO nanowire arrays and the energy band structure change of the heterojunction further confirm the mechanisms. This work not only presents an approach to design high-performance ferroelectric photovoltaic devices but also further broadens the research scope of piezo-phototronics.

Reactive Oxygenated Species Generated on Iodide‐Doped BiVO4/BaTiO3 Heterostructures with Ag/Cu Nanoparticles by Coupled Piezophototronic Effect and Plasmonic Excitation

“…Surprisingly, among the catalysts, BiVO 4 :I/BTO-Ag showed the highest visible light absorbance intensity, which is beneficial to the improvement of photoreaction efficiency. The energy bandgap was calculated from the absorbance spectra using the Tauc equation: [61]…”

Ferroelectric Photovoltaic Materials and Devices

“…Without doping, it is difficult to make up for the shortage of photovoltaic properties of ferroelectric materials. Another way to improve the performance of ferroelectric photovoltaic devices is to combine ferroelectric materials with other materials such as semiconductors [97][98][99][100] Heterojunctions are formed when ferroelectric materials and semiconductor materials come into contact, and the built-in electric field corresponding to formation. The built-in electric field can effectively separate carriers, producing excellent photovoltaic performance externally.…”

“…The most representative semiconductor materials for ferroelectric photovoltaic devices are n-type ZnO and p-type CuO materials. [97,[101][102][103][104][105] It has been shown that photovoltaic devices based on ZnO/BFO heterojunctions exhibited much larger photocurrent than devices based on individual ZnO or BFO. [101,104,106] One of the reasons for this phenomenon is that ZnO has a high internal electron mobility compared to ferroelectric materials.…”

“…Zhang et al achieved further enhancement of ferroelectric photovoltaic signal by using La doping and ZnO nanowire arrays, as shown in Figure 3e. [97] Two times higher photocurrent and shorter response time can be achieved with stain and polarization regulation. There are several advantages to introducing p-type CuO into ferroelectric photovoltaic devices.…”

Comprehensive Study on Piezo-Phototronic Effect: Way Forward for Ferrite Based Solar Cells

“…Zhang et al ( 2020) [36] investigated the piezophototronic effect on La-doped BFO/ZnO heterojunction and observed that rise time of ZnO significantly modulated from 153.7 ms to 61.28 ms. In this study they used la-doped BFO as p-type film and ZnO as n-type film.…”