Realizing High‐Performance BiSbTe Magnetic Flexible Films via Acceleration Movement and Hopping Migration of Carriers

Abstract Improving the thermoelectric (TE) performance of Bi₂Te₃‐based flexible films remains a huge challenge. Herein, high‐performance Ni/epoxy/Bi_0.5Sb_1.5Te₃ magnetic flexible TE films are prepared by incorporating Ni nanoparticles (Ni‐NPs). Atomic‐resolution STEM investigation demonstrates that Te vacancies induced by the orientation reaction between Ni‐NPs and Te from Bi_0.5Sb_1.5Te₃ trigger the presence of negatively charged and anti‐site defects and atomic‐sized electric field in the magnetic flexible TE films and further cause the acceleration movement and hopping migration of carriers. The transport measurements indicate an increased carrier concentration due to the anti‐site defects, while the significant increase of carrier mobility originates from the acceleration movement of carriers. The magnetic scattering and hopping migration of carriers are responsible for maintaining large Seebeck coefficient. As compared to epoxy/Bi_0.5Sb_1.5Te₃ flexible TE film, the maximum power factor of the magnetic flexible TE film with 0.1% Ni‐NPs reaches 2.74 mW m⁻¹ K⁻² at 300 K and increases by 61%, while the cooling temperature difference increases by 250%.