Enhanced Thermoelectric Properties of Ti<sub>2</sub>CO<sub>2</sub>-Bismuthene-Ti<sub>2</sub>CO<sub>2</sub>: Optimized Power Factor and Reduced Thermal Conductivity.

Wu, Yuqiang; Wei, Shafei; Abdulkarim, Sani; Shang, Yuan; Wang, Jingjing; Sun, Mengtao · Nano Lett · 2024

basic_science · Level V

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Abstract

In this study, bismuthene was intercalated between bilayer Ti<sub>2</sub>CTx to induce significant modifications in its electronic and phonon structures, thereby enhancing its thermoelectric properties. First-principles calculations reveal that the insertion of bismuthene transforms the Ti<sub>2</sub>CO<sub>2</sub> system from a semiconductor into a metal and optimizes the thermoelectric properties of bilayer Ti<sub>2</sub>CO<sub>2</sub> by enhancing its power factor and reducing its lattice thermal conductivity. Under the first-principles calculation parameters used in this study, the ZT of the Ti<sub>2</sub>CO<sub>2</sub> system increased from 0.12 to 0.55. Conversely, for metallic bilayer MXenes, the introduction of bismuthene led to a substantial decrease in ZT (from 0.53 to 0.11 in the Ti<sub>2</sub>C system and from 0.07 to 0.05 in the Ti<sub>2</sub>CCl<sub>2</sub> system). This study investigates the physical mechanisms underlying the enhancement of thermoelectric properties from both electronic and phononic perspectives and provides theoretical insights into the development and application of MXene-based thermoelectric materials.