Tan Xiaojian, Shao Hezhu, Hu Tianqi, Liu Guoqiang, Jiang Jun, Jiang Haochuan
Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Science, Ningbo 315201, China.
Phys Chem Chem Phys. 2015 Sep 21;17(35):22872-81. doi: 10.1039/c5cp03466c. Epub 2015 Aug 12.
The thermoelectric properties of two-dimensional graphyne sheets are investigated by using first-principles calculations and the Boltzmann transport equation method. The electronic structure indicates a semiconducting phase for graphyne, compared with the metallic phase of graphene. Consequently, the obtained Seebeck coefficient and the power factor of graphyne are much higher than those of graphene. The calculated phonon mean free path for graphene is 866 nm, which is in good agreement with the experimental value of 775 nm. Meanwhile the phonon mean free path of graphyne is only 60 nm, leading to two order lower thermal conductivity than graphene. We show that the low thermal conductivity of graphyne is due to its mixed sp/sp(2) bonding. Our calculations show that the optimized ZT values of graphyne sheets can reach 5.3 at intermediate temperature by appropriate doping.
通过第一性原理计算和玻尔兹曼输运方程方法研究了二维石墨炔片的热电性质。电子结构表明，与石墨烯的金属相相比，石墨炔为半导体相。因此，所获得的石墨炔的塞贝克系数和功率因数远高于石墨烯。计算得到的石墨烯声子平均自由程为866nm，与775nm的实验值吻合良好。同时，石墨炔的声子平均自由程仅为60nm，导致其热导率比石墨烯低两个数量级。我们表明，石墨炔的低热导率归因于其混合的sp/sp(2)键合。我们的计算表明，通过适当掺杂，石墨炔片的优化ZT值在中间温度下可达到5.3。
