权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

The research on ordered perovskite-type oxide Cd_3TeO_6 with the aim of making new thermoelectric materials

有序钙钛矿型氧化物Cd_3TeO_6的研究，旨在制备新型热电材料

基本信息

批准号：
13650732
负责人：
SHAN Yue Jin
金额：
$ 2.18万
依托单位：
Utsunomiya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

Electron doping into Cd_3TeO_6 with a 1:1 ordered perovskite-type structure was carried out by two methods : the introduction of oxygen vacancies and the atomic substitution of In, Bi and La for Cd. Both methods turned polycrystalline samples into metallic conductors while single crystals with metallic conductivity were obtained by the second method. The resistivity and thermoelectric power of the single-crystal indium-substituted sample were 0.6 mΩ cm and -50 μV/K, respectively, giving a power factor of 4×10^<-4> W K^<-2> m^<-1>, which is the highest among non-transition metal oxides. The good thermoelectric performance of the electron-doped Cd_3TeO_6 derives from its excellent electrical conductivity. Though the reason for the good conductivity is not clear at present, the structural feature of the electron-doped Cd_3TeO_6 may be considered to provide the special electric characteristics of Cd_3TeO_6. The structure of the ordered perovskite oxide Cd_3TeO_6 is strongly deformed (monoc … More linic, P2_1/n), and the Cd-O distances are similar for the cadmium ions in both the A and B sites. Therefore, in the electron-doped Cd_3TeO_6, electrons introduced into the empty 5s orbitals of Cd^<2+> and Te^<6+> can move in the structure through the overlap of the 2p orbitals of the oxide ions not only with the 5s orbitals of the the B-site cations but also with the 5s orbitals of the A-site cadmium ions. This conducting network unique to Cd_3TeO_6 may be related to the high conductivity of this material.In conclusion, we successfully modified the polycrystalline and single-crystal Cd_3TeO_6 samples also by substituting In^<3+> cations for Cd^<2+> ions. The electron doping of the polycrystalline samples could be attained also by introducting oxygen vacancies. This investigation of thermoelectric properties has revealed that the thermoelectric figure-of-merit Z (Z=S^2ρ^<-1>κ^<-1>) of a single crystal, Cd_<3-x>In_xTeO_6, is approximately 1.0×10^<-4> K^<-1> at room temperature. The electron-doped Cd_3TeO_6 is a promising n-type thermoelectric material. Less

采用两种方法对1：1有序钙钛矿结构的Cd_3TeO_6进行电子掺杂：引入氧空位和In、Bi和La原子取代Cd。这两种方法都是将多晶样品转变为金属导体，而第二种方法则得到具有金属导电性的单晶。单晶铟掺杂样品的电阻率和热电势分别为0.6 mΩ cm和-50 μV/K，功率因数为4×10^<-4>W·K^<-2>m^<-1>，是非过渡金属氧化物中最高的。电子掺杂的Cd_3TeO_6具有良好的热电性能，这主要得益于其优良的导电性能。虽然目前尚不清楚Cd_3TeO_6具有良好导电性的原因，但电子掺杂的Cd_3TeO_6的结构特征可能提供了Cd_3TeO_6独特的电学特性。有序钙钛矿型氧化物Cd_3TeO_6的结构发生了强烈的形变（单斜晶系）， ...更多信息 linic，P2_1/n），Cd离子在A和B位的Cd-O距离相似。因此，在电子掺杂的Cd_3TeO_6中，引入到Cd^<2+>和Te^<6+>的5s空轨道的电子不仅可以通过氧化物离子的2 p轨道与B位阳离子的5s轨道的重叠，而且可以通过氧化物离子的2 p轨道与A位镉离子的5s轨道的重叠在结构中运动。这种独特的导电网络可能与Cd_3TeO_6的高电导率有关。总之，我们成功地用In^<3+>离子取代Cd^<2+>离子对多晶和单晶Cd_3TeO_6样品进行了改性。多晶样品的电子掺杂也可以通过引入氧空位来实现。研究表明，室温下Cd_ In_xTeO_6单晶的热电优值Z（Z=S^2ρ^<-1>κ^<-1>）<3-x>约为1.0×10^<-4>K^<-1>。电子掺杂Cd_3TeO_6是一种很有前途的n型热电材料。少