Realizing high thermoelectric properties in p-type polycrystalline SnSe by inducing DOS distortion
Realizing high thermoelectric properties in p-type polycrystalline SnSe by inducing DOS distortion
复制标题
DOI：
10.1007/s12598-021-01753-w
复制
发表时间：
2021-05
期刊：
影响因子：
8.8
通讯作者：
Yuping Wang;Bingchao Qin;Dongyang Wang;Tao Hong;Xiang Gao;Li-dong Zhao
中科院分区：
文献类型：
--
作者：
Yuping Wang;Bingchao Qin;Dongyang Wang;Tao Hong;Xiang Gao;Li-dong Zhao
SnSe晶体由于其优异的热、电输运特性而被认为是最有效的热电材料之一。但多晶SnSe的性能较低，尤其是载流子迁移率和电导率较低。我们首先试图解释和验证的差异，作为温度的函数之间的p型晶体和多晶SnSe的电导率考虑在多晶样品的晶界效应。在2%Na掺杂优化载流子浓度的基础上，进一步引入In提高了多晶SnSe的载流子迁移率，使多晶SnSe的载流子迁移率从3 cm 2 × V-1 × s-1提高到9 cm 2 × V-1 × s-1。In的掺杂在SnSe中引入了额外的共振能级，增加了费米能级附近的态密度，从而提高了SnSe的能带有效质量。在300 K时，Sn 0. 01的Seebeck系数为 * 205 lW × K-1，在773 K时，功率因数为 * 7. 5 lW × cm-1 × K-2。975Na0。02In0. 005 Se样品，在773 K时无量纲品质因数（ZT）超过1.1.
SnSe crystals have been discovered as one of the most efficient thermoelectric materials due to their remarkable thermal and electrical transports. But the polycrystalline SnSe possesses much lower performance especially for the low carrier mobility and electrical conductivity. We firstly attempted to explain and verify the difference in the electrical conductivity as a function of temperature between p-type crystalline and polycrystalline SnSe by considering the grain boundary effects in the polycrystalline samples. On the basis of 2% Na doping to optimize the carrier concentration, the carrier mobility is improved by further introducing In, leading to enhanced carrier mobility from 3 to 9 cm2ÁV-1Ás-1 in polycrystalline SnSe. Moreover, In doping introduces extra resonant levels in SnSe, which increases the density of states near Fermi level and leads to an enhanced band effective mass. Large Seebeck coefficient of* 205 lVÁK-1 at 300K and maximum power factor of* 7.5 lWÁcm-1ÁK-2 at 773 K can be obtained in the Sn0. 975Na0. 02In0. 005Se sample, leading to a competitively high dimensionless figure of merit (ZT) value exceeding 1.1 at 773 K.