MATERIALS • PROCESSES • FINISHES
of the Ag NP connection interface, the researchers proved that low-temperature- sintered Ag NP solder joints have excellent high-temperature (773K) thermal stability. Due to the low sintering temperature (≤ 573 K) and high remelting temperature (> 1200 K) of the Ag NP joint, this connection scheme can theoretically be applied to most thermoelectric device designs over a wide temperature range. For medium-temperature PbTe-based thermoelectric devices, the researchers designed and developed two connection layer structures, Fe-Sb/SnTe/p-PbTe and Fe-Sb/n-PbTe, both of which achieved low interface contact resistance and extremely low thermal expansion coefficient difference, thus guaranteeing the devices’ high performance and reliability. Tis low-temperature Ag Np sintering
process, in combination with structure optimisation via finite element simulation, has reportedly resulted in the best single- stage PbTe-based thermoelectric device reported thus far, achieving an energy conversion efficiency as high as ~11% at a temperature difference of 550K, as well as good thermal cycling reliability. Professor Ren explains: “Tis method significantly reduces the welding temperature of medium- and high-
Fig
2.The two connection layer structures achieved low interface contact resistance and extremely low thermal expansion coefficient difference
temperature thermoelectric devices, ensures the excellent performance of thermoelectric materials, has wide applicability, greatly simplifies the connection process for traditional
thermoelectric devices, and shortens the development cycle for new thermoelectric devices.”
DEMONSTRATING APPLICABILITY To prove the application potential of this method to produce different thermoelectric devices, the researchers additionally designed and fabricated room-temperature Bi2Te3-based thermoelectric devices and high-temperature half-Heusler thermoelectric devices; both of which achieved high energy conversion efficiency in their corresponding temperature ranges.
“Tis design is based on nano-silver sintering technology, and it is very important to know more about this technology in high temperature environments,” Professor Zhang concludes. “We expect to promote the application of thermoelectric devices throughout this research.”
Fig 3. The room-temperature Bi2Te3-based thermoelectric devices and high-temperature half-Heusler thermoelectric devices achieved high energy conversion efficiency
Read the full research paper ‘Low-temperature sintering of Ag nanoparticles for high-performance thermoelectric module design’ at
www.nature.com/articles/s41560- 023-01245-4
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