Bismuth Telluride Supported Sub-1 nm Polyoxometalate Cluster for High-Efficiency Thermoelectric Energy Conversion

Abstract

Size plays a crucial role in chemistry and material science. Subnanometer polyoxometalate (POM) clusters have gained attention in various fields, but their use in thermoelectrics is still limited. To address this issue, we propose the POM clusters as an effective second phase to enhance the thermoelectric properties of Bi 0.4 Sb 1.6 Te 3 . Thanks to their subnanometer size, POM clusters improve electrical transport behavior through the superposition of atomic orbitals and the interfacial scattering effect. Furthermore, their ultrasmall size strongly reduces thermal conductivity. Consequently, the introduction of a mere 0.1 mol % of POM into the Bi 0.4 Sb 1.6 Te 3 matrix realizes a state-of-the-art zT value of 1.46 at 348 K, a 45% enhancement over Bi 0.4 Sb 1.6 Te 3 (1.01), along with a maximum thermoelectricconversion efficiency of the integrated module of 6.0%. The enhancement of carrier mobility and the suppression of thermal conduction achieved by introducing the subnanometer clusters hold promise for various applications, such as electronic devices and thermal management.