Introducing atomistic dynamics at van der Waals surfaces for enhancing thermoelectric performance in layered Bi0.4Sb1.6Te3

Thermoelectric (TE) enables the direct conversion of heat into electricity, but the performance of state-of-the-art layered materials has been limited due to restricted approaches to decoupling carrier and phonon transport. Here, a unique and never-looked feature of intralayer van der Waals bonds/interactions is explored for the atomistic/structural evolution and the transport properties of layered TE materials. The atomistic dynamics governing inversion in van der Waals layers/bonds is established as an innovative material engineering paradigm. We selected layered state-of-the-art Bi_0.4Sb1.6Te3 material as a representative prototype to reveal the intralayer transformative role in realizing high TE performance. The induced atomic diffusion at van der Waals layers and prevailed crystal-amorphicity duality optimize electronic and chemical environment with elevated carrier concentration and maintained Seebeck coefficient, which lead to an improved power factor of ≈ 49 µWcm−1K−2. Besides, the atomistic surface reconstruction/defects cause to reduce thermal conductivity to ≈0.97 Wm−1K−1 and in turn leading to an ultra-high figure of merit (ZTmax) of ≈1.54 at ~373 K. Thus, the present work provides a generic and practical avenue to open up a strategy by unique doping-dependent atomistic engineering, which is expected to be implemented in other layered structures to tailor the TE properties.