High-throughput screening for efficient two-dimensional thermoelectric materials
摘要
A high-throughput ab-initio framework is used to identify two-dimensional materials suitable for thermoelectric applications. Out of 290 experimentally exfoliable materials, a total of 150 monolayers are selected through band gap screening. For these, we compute the thermoelectric transport coefficients and power factor scaled by the relaxation time, S2σ/τ, finding that most of them exceed 5 × 1011 W/mKs. Further screening is then applied by using the average atomic weight criterion. It is found that the p-type monolayers with high S2σ/τ are mostly tetradymites, such as Sb2SeTe2, Bi2STe2, and Bi2SeTe2, except for the less known Sb2SnTe4. In contrast, n-type monolayers with high S2σ/τ are found over a wider range of structures, although typically their S2σ/τ is lower than that of the p-type monolayers. The five best-performing p-type and n-type monolayers are selected for studying their electronic and phonon transport properties. The electronic relaxation time is computed from the electron-phonon coupling matrix, while the lattice thermal conductivity is calculated from the ab-initio force constants up to the third order. Sb2SeTe2 is predicted to provide a high power factor of 26 mW/mK2, while GeTe and Sb2SnTe4 show at 300 K ultra low lattice thermal conductivities of 0.34 and 0.46 W/mK, respectively. Overall the conducted large-scale screening exercise allows us to identify both p-type and n-type monolayers with excellent thermoelectric performance in terms of the figure of merit.