Pb掺杂对Bi-Ca钴酸盐热电材料电子结构的影响研究  

Effect of Pb-doping on Electronic Structure of Bi-Ca Cobaltite Thermoelectric Material

作　　者：邢学玲[1] 罗树琼[1] 吴玉敏[1] 杨雷[1] 

机构地区：[1]河南理工大学材料科学与工程学院,焦作454000

出　　处：《材料导报》2014年第16期143-146,共4页Materials Reports

基　　金：国家自然科学基金(50802025);河南理工大学博士基金(B2006-42)

摘　　要：采用密度泛函离散变分方法计算了Pb掺杂Bi位对EBi1．68Ca2O4]RS[CoO2]1．6。的电子结构和化学键的影响，并讨论了它们与热电性能之间的关系。计算结果表明，掺Pb体系的电子结构表现出半导体特征，与未掺杂的相比，能隙变窄；掺Pb后，在-4．5～1．8eV的能量范围内，高能态Co3d与低能态O2p存在着杂化作用，Pb6p在费米能级附近的贡献增强。通过计算键级和分子波函数轨道可知，体系的计算键级在曲面和C轴方向表现出各向异性特征，掺Pb后，Co-O、Pb（Bi）-O均比未掺杂体系减弱，而Bi（Pb）-Bi的键性增强。由此推断，掺Pb体系的热电性能将有所改善。The relations among electronic structure, chemical bonds and thermoelectric properties of [-Bi1.68- Ca2O4 ]RS[CoO2]1. 69 with Pb-substituted-Bi were analyzed by density function theory and discrete variational method （DFT-DVM）. The results include that the property of semiconductor is showed obviously by electronic structure of Pb-doped one and the gap of the highest valence band and the lowest conduction band becomes narrower than the undo- ped, and higher hybridization is appeared between Co 3d with high energy state and O 2p with low state in the range of --4. 5 eV and 1.8 eV, and that contribution of Pb 6p atomic orbitals become stronger near Fermi level. It can be found from covalent bonds and molecular orbitals that anisotropy property of both systems are shown obviously by difference of chemical bonds in ab-plane and c axis, and that Co-O,Pb（Bi）-O are lower, but the covalent bonds of Bi（Pb）-Bi become stonger after Pb-doped. So the thermoelectric properties of [Bi1. 68 Ca2O4 ]RS[CoO2]1.69 can be improved by replacing the Bi-site atoms with Pb atoms.

关 键 词：失配层结构 电子结构 化学键 热电性能 

分 类 号：Q641.12[生物学—生物物理学]