High thermoelectric performance of intrinsic few-layers T-HfSe2

Abstract

Due to their distinct electrical, mechanical, thermal, and optoelectronic properties, two-dimensional layered materials have drawn a lot of research and interest. This study employs first-principles calculations along with Boltzmann transport theory to precisely predict the thermoelectric properties of few-layer intrinsic (2 L, 3 L, and 4 L) T -HfSe 2 . The increase in layers causes band degeneracy, which greatly improves the Seebeck coefficient and power factor, we obtain an amazingly high power factor of 1.2 × 10 13 cm −3 at room temperature. Meanwhile, the lattice thermal conductivity of few-layer intrinsic T -HfSe 2 is found to be lower than that of monolayer caused by van der Waals interactions. Ultimately, a maximum p-type ZT value of ~0.53 can be reached at 300 K, which is close to the ZT value of ~0.6 for the latest work GeTe-based TE materials. Moreover, we obtai n n -type ZT of ∼1.3, which is amazingly high and close to Pb-doped SnSe ~1.2. The results indicate that layered HfSe 2 is quite an excellent thermoelectric material at room temperature. In summary, this work demonstrates the tremendous advantages of few-layered HfSe 2 in thermoelectric applications.