Dielectric, ferroelectric and photoluminescence properties of Er3+ doped Bi4Ti3O12 ferroelectric ceramics
Dielectric, ferroelectric and photoluminescence properties of Er3+ doped Bi4Ti3O12 ferroelectric ceramics
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DOI：
10.1016/j.ceramint.2015.01.062
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发表时间：
2015-05-01
影响因子：
5.2
通讯作者：
Sreenivas, K.
中科院分区：
文献类型：
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作者：
Bokolia, Renuka;Thakur, O. P.;Sreenivas, K.
研究了掺Er(Er)钛酸铋(Bi4-xErxTi3O12)陶瓷的结构、电学和发光转换性能。确定了单相Bi4Ti3O12的晶胞为正交晶系，并且发现随着掺Er量(X)的增加，单相Bi4Ti3O12的晶型变形量减小。发现Bi2Ti4O11第二相(-lt；5wt%)的存在是由于铋的损失，并且随着Er3+含量(X)的增加而减少。在较高的Er含量x>；0.2时，随着晶粒度的增大，具有随机取向的片状组织发生突变。拉曼光谱表明，改性组分中的(Bi2O2)(2+)层未受影响，Er3+取代Bi3+主要发生在钙钛矿块的A位，导致阳离子无序和TiO6八面体畸变率降低。在较宽的频率范围内(10(-2)至10(6)Hz)，增加Er的取代度可降低介电损耗和介电损耗，降低介电损耗和介电色散。在980 nm激发下(x=0.2)，在527、548和662 nm处分别观察到较强的UC发光，并分别归因于H-2(11/2)->；I-4(15/2)、S-4(3/2)->；I-4(15/2)和F-4(9/2)->；I-4(15/2)跃迁。随着Er含量的增加(x>；0.2)，由于交叉弛豫(CR)过程，样品的发光发生了明显的猝灭，铁电性能下降。但当Er含量增加到x=0.3时，材料的电导率、介电损耗和介电色散显著降低。(C)2015年爱思唯尔有限公司和Techna Group S.r.l.版权所有。
Structural, electrical, and light up conversion properties of Erbium (Er) substituted bismuth titanate (Bi4-xErxTi3O12) ceramics have been investigated. Formation of single phase Bi4Ti3O12 with orthorhombic unit cell is confirmed, and orthorhombic distortion is found to decrease with increasing erbium content (x). Presence of Bi2Ti4O11 secondary phase (< 5 wt%) is detected due to bismuth loss, and is found to decrease with increasing erbium content (x). A randomly oriented plate like microstructure with increasing grain size is found to change abruptly at higher erbium content x>0.2. Raman spectroscopy reveals that (Bi2O2)(2+) layers remain unaffected in the modified compositions, and Er3+ substitution for Bi3+ occurs predominantly at the A-site in the perovskite blocks leading to cationic disorder and a decrease in the TiO6 octahedral distortion. Increasing Er substitution results in reduced dielectric losses and reduced dispersion in epsilon' and tan delta over a wide frequency range (10(-2) to 10(6) Hz). Strong UC luminescence at 527, 548 and 662 nm is seen under an excitation of 980 nm for an optimum erbium content (x=0.2) and is attributed to the transitions H-2(11/2) -> I-4(15/2), S-4(3/2) -> I-4(15/2) and F-4(9/2) -> I-4(15/2) respectively. Increasing Er content (x > 0.2) exhibits pronounced luminescence quenching due to cross-relaxation (CR) process, and degrades the ferroelectric properties. However the electrical conductivity, dielectric losses and dielectric dispersion reduce considerably with increasing Er content up to x=0.3. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.