采用玻尔兹曼输运方程与密度泛函计算相结合的方法,理论研究了限域效应与界面效应对SrTi03纳米陶瓷热电性能的影响.理论计算的结果表明,室温下纳米陶瓷的热电优值较单晶有了大幅度提高,可达到0.8.热电优值的提高主要来源于晶粒内的声子限域效应与电子在晶界处的界面能量过滤效应,电子的限域效应与声子的界面散射效应起到了辅助作用.本文结论也可推广至其他材料,因此对高性能热电纳米陶瓷的设计将起到积极的作用.
The influences of electron and phonon confinement and interface effects on the thermoelectric performance of SrTiO3 nano- ceramic are studied by using the Boltzmann transport equations and density functional calculations. Theoretical calculations show that the figure of merit of nano-ceramic is greatly improved up to 0.8 at room temperature. The improvement is due mainly to the phonon confinement effect and the electronic energy filtering effect at the grain boundary. The electron confinement effect and the interface phonon scattering effect play a supporting role. These results may be conducive to the design of high-performance thermoelectric nano-ceramic.