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

Abstract

Improving the thermoelectric (TE) performance of Bi 2 Te 3 -based flexible films remains a huge challenge. Herein, high-performance Ni/epoxy/Bi 0.5 Sb 1.5 Te 3 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 0.5 Sb 1.5 Te 3 trigger the presence of negatively charged ( ) ′′′ ′′′ V V V V B Bi i S Sb b and ( ( ) ) ′ ′ B Bi i S Sb b T Te e T Te e 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 0.5 Sb 1.5 Te 3 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%.

Magnetic‐Anisotropy‐Enhanced Electrical Transport Properties of Co/Bi0.5Sb1.5Te3/PVDF Flexible Thermoelectromagnetic Films

“…[25] The reaction equations are as follows: ′ ′ established atomic-scale micro-electric fields in the carrier transport channel, which can accelerate the carrier movement and cause carrier hopping migration, promoting the increase of carrier mobility. [24] On the other hand, the BST/CoTe 2 /Co heterointerface also produces carrier energy filtering effect, which can effectively scatter low-energy carriers without affecting the high-energy carrier transport. [31][32][33] The M-H curves of Co/BST/PVDF films are shown in Figure 6b-d.…”

“…[19][20][21][22][23] Recently, our group found that magnetic metal nanoparticles Co and Ni can undergo in situ reaction and orientation reaction with Bi 0.5 Sb 1.5 Te 3 (BST), resulting in accelerated carrier movement and hopping migration, and successfully prepared Bi 2 Te 3 -based flexible magnetic TE films with high electrical transport properties. [24,25] Thus, more and more researches have proved that magnetic recombination is an effective means to improve the electrothermal conversion performance of TE materials. However, how to control the direction of the built-in micro-magnetic field in TEM composites has not yet been reported.…”

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

“…13,27,28 Lately, high-performance thermoelectromagnetic (TEM) lms, developed based on the magnetically enhanced TE effect, [29][30][31] are also proposed as an effective strategy of optimizing the electrical transport properties. 32,33 For example, magnetic metal nanoparticles (NPs) were introduced into Bi 2 Te 3 -based lms, which led to a signicant enhancement in the electrical transport and cooling properties of the prepared TE lms via the thermo-electro-magnetic coupling effect. [33][34][35] These results demonstrate that the presence of certain magnetic properties and conductive channels can signicantly increase the electro-thermal conversion performance, and then a high-performance TEM lm can be created by combining the relevant magnetic properties and conductive channels.…”

“…32,33 For example, magnetic metal nanoparticles (NPs) were introduced into Bi 2 Te 3 -based lms, which led to a signicant enhancement in the electrical transport and cooling properties of the prepared TE lms via the thermo-electro-magnetic coupling effect. [33][34][35] These results demonstrate that the presence of certain magnetic properties and conductive channels can signicantly increase the electro-thermal conversion performance, and then a high-performance TEM lm can be created by combining the relevant magnetic properties and conductive channels. However, the impact of structural relationships on the TE properties of multilayer TE lms, which feature a combination of correlated magnetic properties and conductive channels, has not yet been explored.…”

Fine-Tuning Bi2Te3-Copper Selenide Alloys Enables an Efficient n-Type Thermoelectric Conversion

“…As both the practical need and the worldwide market for wearable and implantable electronics are increasing rapidly [ 1 , 2 ], flexible thermoelectric (FTE) materials, which are fundamental in the manufacturing of such devices, have been receiving particular attention in recent years. To maximize the electro-thermal conversion efficiency and reachability [ 3 ], the FTE materials should exhibit satisfactory thermoelectric properties at a relatively low temperature range [ 4 , 5 ]. Among all kinds of TE materials, bismuth telluride-based materials are considered some the most attractive and promising FTE materials for both p-type and n-type TE applications to date [ 6 , 7 , 8 , 9 ].…”