缺陷离子调控对BiFeO3-BaTiO3基钙钛矿材料的铁电光伏特性影响  

Effect of regulation of defect ion on ferroelectric photovoltaic characteristics of BiFeO3-BaTiO3 based perovskite materials

作　　者：朱立峰[1] 潘文远 谢燕 张波萍[1] 尹阳 赵高磊[2] Zhu Li-Feng;Pan Wen-Yuan;Xie Yan;Zhang Bo-Ping;Yin Yang;Zhao Gao-Lei(School of Material Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China;Institute of Acoustics,Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]北京科技大学材料科学与工程学院,北京100083 [2]中国科学院声学研究所,北京100190

出　　处：《物理学报》2019年第21期271-279,共9页Acta Physica Sinica

基　　金：中央高校基本科研业务费(批准号:FRF-TP-18-005A2)资助的课题~~

摘　　要：BiFeO3-BaTiO3铁电材料具有优异的压电和铁电性能,近年来受到广泛的关注.该材料既保持了BiFeO3体系高的自发极化强度Ps的优点,也克服了BiFeO3体系难以合成纯钙钛矿相等缺点,被认为是非常有前景的铁电、压电以及光伏材料.本文采取传统固相法制备了Bi(Fe0.96Mg0.02– xTi0.02+x)O3-0.3BaTiO3铁电陶瓷,并揭示了Mg^2+/Ti4^+比例的变化对该陶瓷样品的铁电和压电以及光电性能的影响.由于Ti4+取代Mg^2+产生电子,导致陶瓷样品的导电性能增加,压电和铁电性能出现恶化,其压电系数d33从x=0的195 pC/N下降至x=0.02时的27 pC/N.与之相反的是,Ti4^+取代Mg^2+扩宽了陶瓷样品的光吸收范围,使陶瓷样品的禁带宽度由x=0的1.954 eV下降至x=0.02时的1.800 eV.由于偶极子翻转构建的内偏电场和禁带宽度的降低等方面的相互作用,陶瓷样品的光电流密度J由x=0时的3.71 nA/cm^2增加至x=0.02时的32.45 nA/cm^2.Ferroelectrics materials, as a candidate of materials, have recently received attention, for they possess applications in photovoltaic devices and can couple the light absorption with other functional properties. In these materials, the strong inversion symmetry is broken, which is because the spontaneous electric polarization promotes the desirable separation of photo-excited carriers and allows voltages higher than the band-gap, thus permitting efficiency beyond the maximum possible value in a conventional p-n junction solar cell. Much effort has been made to study the ferroelectric photovoltaic effect in several families of ferroelectric perovskite oxides,such as Pb(Zr,Ti)O3, LiNbO3, BaTiO3, KNbO3, Na0.5 Bi0.5 TiO3-BaTiO3, AgNbO3 and BiFeO3. However, their photo-electric conversion efficiency is now still very low though this field is being studied. The observed output photocurrent is very low due to the negative influence of a wide band-gap and small absorption coefficient,which is caused by the wide band-gaps for most of ferroelectric materials such as Pb(Zr,Ti)O3(~3.5 eV), and BaTiO3(~3.3 eV), especially. Although the BiFeO3 system with low band-gap(2.7 eV), which can absorb most visible light for electron transition, is considered as a potential photovoltaic material, it is difficult to synthesize pure perovskite structure. The BiFeO3-BaTiO3(BF-BT) ferroelectric material with excellent piezoelectric and ferroelectric properties has been widely concerned by researchers in recent years. However, it is still unclear whether this system has the same advantages as BiFeO3 materials with excellent photovoltaic properties. In this work, the Bi(Fe0.96Mg0.02– xTi0.02+x)O3-0.3 BaTiO3 ferroelectric ceramics are prepared by the conventional synthesis method to uncover the piezoelectric and ferroelectric properties, as well as the photovoltaic performance with different ratios of Mg^2+/Ti4. Because of the electronic production caused by replacing Mg2+ions with Ti4+ ions, the conductivity of sample increases, and thus

关 键 词：铁酸铋 铁电材料 光伏特性 钙钛矿结构 

分 类 号：TM221[一般工业技术—材料科学与工程]