Enhanced Antioxidation and Thermoelectric Properties of the Flexible Screen-Printed Bi₂Te₃ Films through Interface Modification

Abstract

With the advantages of easy processing and mass production, printing technologies to fabricate flexible thermoelectric films have received widespread scientific and technological interest. In this work, interface modification has been applied to effectively improve the loose porous intrinsic structure of screen-printed Bi2Te3 thermoelectric films, thus regulating the antioxidation and thermoelectric properties. Specifically, nanosolder is prepared and introduced into the screen-printing technique, which can modify the interface and thus enhance the electrical conductivity in the screen-printed film. Accordingly, a highest power factor of 3.63 μW cm–1 K–2 is obtained and the ZT over 0.2 is achieved in a wide temperature range from 300 to 460 K. Meanwhile, the role of the inert gas (N2) and the reducing atmosphere (Ar/H2, 5% H2 + 95% Ar) during the sintering process of screen-printed Bi2Te3 films is also revealed. The film with nanosolder sintered in N2 has excellent oxidation resistance through the interface modification of thiol molecules. However, the hydrogen atmosphere damages the antioxidation according to the gas-induced defect engineering. Through the introduction of nanosolder, the electrical resistivity change of the screen-printed film is just about 3.6% after being stored for 6 months in air, and it can withstand repeated bending for 1000 times (concave) or 600 times (convex) when the bending radius is as low as 20 mm. Our research provides an effective method for preparing high-quality flexible thermoelectric films and greatly facilitates the development of screen-printed flexible wearable thermoelectric devices.

Recent Progress of Two-Dimensional Thermoelectric Materials

“…Recently, 2D TMDCs have collected a wide attention due to their special properties and are considered to be the next generation of high-performance thermoelectric materials [70,74,90,[175][176][177][178][179][180]. The measured Seebeck coefficient of single-layer MoS 2 can measure over 30 mV K −1 , providing an ideal candidate material for high-performance thermoelectric devices.…”

Design guidelines for chalcogenide-based flexible thermoelectric materials

“…The common flexible substrates are polyimide (PI), polyether sulfone (PES) 14 , and polyvinylidene fluoride (PVDF) 15,16 ; inorganic nanostructure-based films can maintain flexibility. The common fabrication processes are magnetron sputtering [17][18][19][20][21][22][23] , pulsed laser deposition [24][25][26] , thermal evaporation 27,28 , vacuum-assisted filtration and screen printing 29,30 , etc. Some additional methods like cold pressing and hot pressing 5,31 can maintain the comparable bulk- 6 The electron conductivity is enhanced by Ag, which ejects electrons into the conduction band of the other two composites.…”

New frontier in printed thermoelectrics: formation of β-Ag2Se through thermally stimulated dissociative adsorption leads to high ZT

“…The resulting printable composite can then be printed through various printing techniques, e.g., screen printing or ink-jet printing, onto mechanically exible substrates and subsequently sintering them. [4][5][6] However, development of printable thermoelectric inks resulting in high efficiencies is a key challenge in the eld. The rheological adaptation of TE inks to the different printing techniques by introducing non-conductive additives and solvents oentimes leads to an overall reduced ZT value compared with the base thermoelectric material.…”

“…4 In an alternative approach, a power factor value of 3.63 mW cm À1 K À2 with ZT over 0.2 was attained in a screen-printed Bi 2 Te 3 lm through interface modication. 6 Inkjet printed Bi 2 Te 3 and Bi 0.5 Sb 1.5 Te 3 exible nanowires were reported to reach power factors of 1.80 mW cm À1 K À2 and 1.10 mW cm À1 K À2 , respectively, through post-print thermal annealing. 16 Organic materials on the other hand offer a much easier path towards printability.…”