Polarization dependent ferroelectric photovoltaic effects in BFTO/CuO thin films

Abstract

Bi5FeTi3O15 (BFTO) and BFTO/CuO films were deposited by a sol-gel technique, which exhibited macroscopic ferroelectric properties. It was found that the BFTO/CuO films showed a short circuit photocurrent density (Jsc) enhanced by nearly 10 times and power conversion efficiency increased by 13-fold compared to those of the BFTO film. The significant increase in the photovoltaic (PV) response may be attributed to the p-n junction internal electric field acting as the driving force of photogenerated carriers. Furthermore, both BFTO and BFTO/CuO films indicated a switchable PV response in both polarities. The open circuit voltage (Voc) and Jsc for BFTO and BFTO/CuO were observed to be −0.59 V and +43.88 μA/cm2 and −0.23 V and +123.16 μA/cm2, respectively, after upward poling, whereas after downward poling, +0.11 V and −6.26 μA/cm2 and +0.17 V and −83.21 μA/cm2 for BFTO and BFTO/CuO were observed, respectively. The switchable PV responses were explained by the ferroelectric depolarization field, whose direction could be altered with the variation in the applied poling field. This work provides an efficient approach to developing ferroelectric film based PV devices with low cost.

Inorganic photovoltaic cells based on BiFeO3: spontaneous polarization, lattice matching, light polarization and their relationship with photovoltaic performance

“…In addition, the depolarization field is anti-correlation with the thickness of the cell. One of the candidate materials of the BPV effect perovskites is Bismuth Ferrite [1,7,[18][19][20][21][22][23][24][25][26][27][28][29][30] (BiFeO 3 , or BFO). The extensively studied BFO is a multiferroic material which has the multiple properties of ferroelectric, anti-ferromagnetic, and ferroelastic [31].…”

Ferroelectric Photovoltaic Materials and Devices

“…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.…”

Progress and Perspectives on Aurivillius-Type Layered Ferroelectric Oxides in Binary Bi4Ti3O12-BiFeO3 System for Multifunctional Applications

“…Kim et al [156] reported electrical and structural properties of metal-ferroelectric-insulator-semiconductor Au/Bi 3.25 La 0.75 Ti 3 O 12 /HfO 2 /Si structure as the nonvolatile-memory field-effect transistors, by varying the HfO 2 buffer layer thickness. Zhu et al [157] found that the 2P r and coercive field (E c ) of the BFTO-4/CuO films are 29.40 µC/cm 2 and 54 kV/cm, respectively, while the values for the BFTO-4 film are 46.32 µC/cm 2 and 146 kV/cm, respectively. Obviously, 2P r and E c are significantly reduced after the introduction of the CuO buffer layer, due to the good conductivity of the CuO.…”

“…Zhu et al [157] showed the polarization-regulated PV effect in CuO/BFTO-4 films fabricated on fluorine-doped tin oxide (FTO) glass substrate. For the Au/BFTO-4/FTO and Au/CuO/BFTO-4/FTO devices, the PV effect and power conversion efficiency of the BFTO-4 was improved by the addition of the CuO buffer layer, resulted from the formed pn junction at the CuO/BFTO-n interface (Figure 13a).…”