Reporter learned from the Chinese Academy of Sciences, Hefei Institute of Physical Science, Institute of solid material computing science research room researcher Zhang Yongsheng research group made new progress in the study of low thermal conductivity of thermoelectric materials, the relevant results recently published in the internationally renowned "Physics Review B" .
The thermoelectric material can realize the conversion between thermal energy and electric energy, the conversion efficiency can be measured by dimensionless ZT value, the larger the ZT value is, the higher the thermoelectric conversion efficiency is.At present, the conversion efficiency of thermoelectric materials reported is relatively low, Materials with low thermal conductivity are an important method to improve the conversion efficiency of thermoelectric materials.Because of its low thermal conductivity and low cost, ore materials have attracted much attention of researchers. Two isomorphic ore materials CuBiS 2And CuSbS 2The experimentally measured values of thermal conductivity vary widely at room temperature for CuBiS 2The thermal conductivity is only CuSbS 21/3, so to explore the physical mechanism that affects the low thermal conductivity of the material is of great significance for the design and search for new materials.
To this end, Zhang Yongsheng researcher group researchers using density functional theory method to study the CuBiS 2Relative to CuSbS 2Physical mechanism with lower thermal conductivity. Studies have shown that CuBiS 2And CuSbS 2Both Bi and Sb atoms contain lone pair electrons, whereas lone pairs of electrons lead to strong non-harmonic material, which in turn leads to lower thermal conductivity of both lone pairs of electrons and atoms Synergies lead to CuBiS 2Relative to CuSbS 2Has lower thermal conductivity.Related studies show that the synergistic effect of lone pair electrons and atomic vibrations has an important influence on the non-harmonic phonon.
This research result will provide a new idea for seeking and designing new thermoelectric materials with ultra-low thermal conductivity and high efficiency.
