High thermoelectric performance in two-dimensional graphyne sheets predicted by first-principles calculations
High thermoelectric performance in two-dimensional graphyne sheets predicted by first-principles calculations
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第一性原理计算预测二维石墨烯片的高热电性能
DOI：
10.1039/c5cp03466c
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发表时间：
2015
影响因子：
3.3
通讯作者：
Jiang Haochuan
中科院分区：
文献类型：
--
作者：
Tan Xiaojian;Shao Hezhu;Hu Tianqi;Liu Guoqiang;Jiang Jun;Jiang Haochuan
采用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烯片的热电性质。与石墨烯的金属相相比，电子结构指示石墨炔的半导体相。因此，所获得的石墨烯的塞贝克系数和功率因数远高于石墨烯。计算得到的石墨烯的声子平均自由程为866 nm，与实验值775 nm吻合较好。同时石墨炔的声子平均自由程仅为60 nm，导致热导率比石墨烯低两个数量级。我们表明，石墨炔的低热导率是由于它的混合sp/sp2键。计算结果表明，通过适当的掺杂，石墨炔片在中温下的最佳ZT值可以达到5.3。
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/sp2 bonding. Our calculations show that the optimized ZT values of graphyne sheets can reach 5.3 at intermediate temperature by appropriate doping.