摘要
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 cm2·V^(-1)·s^(-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 l V·K^(-1) at 300 K and maximum power factor of ~7.5 l W·cm^(-1)·K^(-2) at 773 K can be obtained in the Sn_(0.975)Na_(0.02)In_(0.005) Se sample,leading to a competitively high dimensionless figure of merit(ZT) value exceeding 1.1 at 773 K.
出处
《Rare Metals》
SCIE
EI
CAS
CSCD
2021年第10期2819-2828,共10页
稀有金属（英文版）
基金
financially supported by the National Key Research and Development Program of China (Nos.2018YFA0702100 and 2018YFB0703600)
the National Natural Science Foundation of China (Nos.51772012 and 51671015)
Beijing Natural Science Foundation (No.JQ18004)
National Postdoctoral Program for Innovative Talents (No.BX20200028)
the support from the National Science Fund for Distinguished Young Scholars (No.51925101)
the high performance computing (HPC) resources at Beihang University。
