Enhanced N-Type Bismuth-Telluride-Based Thermoelectric Fibers via Thermal Drawing and Bridgman Annealing

Abstract

N-type bismuth telluride (Bi2Te3) based thermoelectric (TE) fibers were fabricated by thermal drawing and Bridgman annealing, and the influence of Bridgman annealing on the TE properties of n-type Bi2Te3-based TE fibers was studied. The Bridgman annealing enhanced the electrical conductivity and Seebeck coefficient because of increasing crystalline orientation and decreasing detrimental elemental enrichment. The TE performance of n-type Bi2Te3-based TE fibers was improved significantly by enhancing the power factor. Hence the power factor increased from 0.14 to 0.93 mW/mK2, and the figure-of-merit value is from 0.11 to 0.43 at ~300 K, respectively.

High-Performance n-Type Bi2Te3 Thermoelectric Fibers with Oriented Crystal Nanosheets

“…To date, it has been found that the n-type Bi 2 Te 3 fibers (thermally drawn with glass cladding by a powder-in-tube method) could exhibit a restricted ZT < 0.5 owing to the low relative density and more texturing-related sensitivity of the carriers’ mobility than their p-type fibers ( ZT ~1.4) [ 9 ]. In the thermoelectric fibers fabricated by thermal drawing from our previous works [ 14 , 15 , 16 , 17 ], the c -plane crystalline orientation enhances the carrier mobility and electrical conductivity in Bi 2 Te 3 core fibers.…”

“…Herein, high-performance n-type Bi 2 Te 3 fibers were fabricated by a rod-in-tube thermal drawing method, and subsequent annealing processes (whole annealing and Bridgman annealing) were used to enhance the crystallization of two kinds of opposite crystalline orientations [ 17 ]. Crystalline orientations along (110) and (001) in the fiber cores were increased by whole annealing and Bridgman annealing, respectively, and the elemental enrichment was reduced.…”

Advances in Thermoelectric Composites Consisting of Conductive Polymers and Fillers with Different Architectures

“…Although TE materials are promising and have lots of advantages, predominant inorganic TE materials (such as Sb 2 Te 3 , Bi 2 Te 3 , etc.) are extremely limited in their application for wearable, portable, and implantable electronic devices and flexible robots due to the scarcity, toxicity, expensiveness, and difficulty in processing [ 8 , 9 , 10 , 11 ]. Fortunately, composites which consist of conductive polymers and fillers with different architectures, such as inorganic semiconductors or carbon nanoparticles, can balance properties with needs.…”