Jo Hongil, Kim Yeong Hun, Lee Dong Woo, Ok Kang Min
Department of Chemistry, Chung-Ang University, Seoul, 156-756, Republic of Korea.
Dalton Trans. 2014 Aug 14;43(30):11752-8. doi: 10.1039/c4dt01060d. Epub 2014 Jun 24.
Y(3+)-doped noncentrosymmetric (NCS) bismuth tellurite materials, Bi(2-x)Y(x)TeO5 (x = 0, 0.1, and 0.2), have been synthesized through standard solid-state reactions and structurally characterized by powder neutron diffraction. The reported NCS materials crystallize in the orthorhombic space group Abm2 (no. 39), and exhibit pseudo-three-dimensional frameworks that are composed of BiO3, BiO5, and TeO3 polyhedra. Detailed diffraction studies show that the cell volume of Bi(2-x)Y(x)TeO5 decreases with an increasing amount of Y(3+)on the Bi(3+) sites. However, no ordering between Bi(3+) and Y(3+) was observed in the Bi(2-x)Y(x)TeO5. Powder second-harmonic generation (SHG) measurements, using 1064 nm radiation, reveal that Bi2TeO5, Bi(1.9)Y(0.1)TeO5, and Bi(1.8)Y(0.2)TeO5 exhibit SHG efficiencies of approximately 300, 200, and 60 times that of α-SiO2, respectively. The reduction in SHG for Y(3+)-doped materials is consistent with the lack of net moment originating from polyhedra with a polarizable Bi(3+) cation.
通过标准固态反应合成了Y(3+)掺杂的非中心对称（NCS）碲酸铋材料Bi(2-x)Y(x)TeO5（x = 0、0.1和0.2），并通过粉末中子衍射对其结构进行了表征。报道的NCS材料结晶于正交空间群Abm2（编号39），呈现出由BiO3、BiO5和TeO3多面体组成的伪三维框架。详细的衍射研究表明，Bi(2-x)Y(x)TeO5的晶胞体积随着Bi(3+)位点上Y(3+)含量的增加而减小。然而，在Bi(2-x)Y(x)TeO5中未观察到Bi(3+)和Y(3+)之间的有序排列。使用1064 nm辐射进行的粉末二次谐波产生（SHG）测量表明，Bi2TeO5、Bi(1.9)Y(0.1)TeO5和Bi(1.8)Y(0.2)TeO5的SHG效率分别约为α-SiO2的300、200和60倍。Y(3+)掺杂材料的SHG降低与源自具有可极化Bi(3+)阳离子的多面体的净矩缺乏一致。
