Interlayer carrier high-speed conductive channels and excellent electrical transport performance of multilayer films

Abstract

Currently, the most promising breakthrough to the main bottleneck of in-plane heat dissipation technology based on the Peltier effect is the development of high-performance thermoelectric (TE) films. Herein, a series of p-type Bi_0.5Sb_1.5Te₃ (BST)/xFe-BST epoxy multilayer films (Fe nanoparticles (Fe-NPs)-BST (Fe-BST) layer x = 0, 1, 2, 3 and 4) were designed and prepared by inserting a magnetic layer into two TE layers. The metallic magnetic Fe-NP layers as electron carrier expressways were introduced into BST epoxy multilayer films to produce a high-speed conductive channel and extra interlayer magnetic scattering to improve the electrical transport performance of the BST epoxy multilayer films. The electrical conductivity of the BST/xFe-BST epoxy multilayer films is significantly increased due to a surge in carrier mobility. Magnetoresistance shows that the Fe-NP layer in BST/xFe-BST epoxy multilayer films is able to produce extra interlayer magnetic scattering (spin-dependent scattering and weak-localization pinning), suppressing the decrease of the Seebeck coefficient. As a result, the maximum power factor (2.29 × 10⁻³ W K⁻² m⁻¹) of BST/Fe-BST epoxy multilayer films increased by 139% compared to that of the BST epoxy multilayer film, and the maximum cooling temperature difference was enhanced by 1.2 times. The interlayer coupling between magnetic/TE layers is utilized to introduce a new effect of thermo-electro-magnetic coupling in this study, which endowed the thermoelectromagnetic films with certain magnetic properties and significantly enhanced TE conversion performance, providing a new way for the preparation of high-performance TE films.