Pr/Nb共掺Bi_4Ti_3O_(12)铋层状陶瓷的光致发光与电性能研究

Photoluminescence and electric properties of Pr/Nb codoped Bi_4Ti_3O_(12) bismuth layered-structure ceramics

Bi_4Ti_3O_(12)是一种兼具有高居里温度和高电阻率的铋层状结构压电材料.本文利用Pr^(3+),Nb^(5+)分别对其A位Bi^(3+)和B位Ti^(4+)进行掺杂改性,采用传统固相法制备了Bi_(4-x)Pr_xTi_(2.92)Nb_(0.08)O_(12)(BITN-xPr,0≤x≤0.1)陶瓷,通过控制Nb^(5+)离子的量不变,调节Pr^(3+)离子的浓度来研究不同稀土离子掺杂量对Bi_4Ti_3O_(12)陶瓷的结构形貌、光致发光、介电以及铁电压电性能的影响.经X射线衍射(XRD)测试表明所有样品都具有单一正交相结构,且扫描电子显微镜(SEM)显示陶瓷具有层状形貌特征,拉曼光谱表明Pr^(3+)离子取代钙钛矿层的A位Bi^(3+)离子,导致TiO6八面体发生扭曲.通过蓝光和紫外激光对Bi_(4-x)Pr_xTi_(2.92)Nb_(0.08)O_(12)陶瓷进行激发,可获得红色发光,使其有望作为红色荧光粉应用于蓝色基的白光LED照明.随着Pr浓度的增加,红色发光强度呈现出先增强后减弱的规律,居里温度表现出小幅度下降;另外,陶瓷的压电铁电性能均得到一定程度的改善,以上结果表明Bi_(4-x)Pr_xTi_(2.92)Nb_(0.08)O_(12)陶瓷是一种兼具铁电压电以及光致发光性能的多功能材料.

Bi_4Ti_3O_（12）（BIT） belongs to bismuth-layer structure piezoelectric materials, along with high Curie temperature（Tc） and high resistivity.Pr/Nb co-doped BIT piezoelectric ceramics were synthesized by conventional solid-state reaction method and their structural,up-conversion luminescent and dielectric properties were investigated in this study. The substitution of Nb^（5＋） ion was fixed as 0.08 mol and the amount of Pr^（3＋） was 0≤x≤0.1. The X-ray diffraction data showed that the samples were single phase with orthorhombic unit cell, and SEM micrographs revealed that the samples have similar plate-like grain morphology. Raman spectroscopy revealed that Er^（3＋） substitution for Bi^（3＋） occured predominantly at the A-site in the perovskite blocks. The red emission was observed under the ultraviolet and blue light excitation at room temperature, which is adaptable to the emission band of commercial blue light-emitting diodes（LEDs） chips. With increasing Pr^（3＋） content, the intensity of the photoluminescence increased initially and then decreased due to concentration quenching. The Tc was slightly shifted to the lower temperature, the piezoelectric and ferroelectric properties was both enhanced by doping. These results indicated the Pr doped BITN ceramics were a kind of multifunctional materials with excellent optical performance.