Development of a solid-state multi-stage thermoelectric cooler

In this work, a unique thermoelectric solid-state multi-stage cooler for operating temperatures up to ~140 K was developed. The extrusion technology was applied to fabricate thermoelectric legs with sufficient mechanical properties for the device construction. A cooling prototype was designed and fabricated using a four-stage commercial module and a two-stage ultra-low temperature module. The ultra-low temperature module, operating in the temperature range of 180–140 K, was fabricated using Bi_0·91Sb_0.09 alloys as an n-type leg and an optimized composition of Bi_1·6Sb_0·4Te₃ as a p-type leg. The four-stage commercial thermoelectric module based on n- and p-type Bi₂Te₃ based alloys was utilized for operation in the temperature range of 180–300 K. The solid-state cooler was tested at a hot temperature T_h = 300 K in a vacuum. At the cold temperature of the fourth stage 180 K, the maximum temperature difference of the ultra-low temperature module achieves high values of maximum temperature difference ΔT = 45 K and maximum cooling capacity Q_c = 85 mW. Furthermore, we demonstrated the applicability of the ultra-low cooler for refrigeration up to 150 K for a mid-infrared sensor based on a PbTe photodiode with a cut-off wavelength λ_c ≈ 4.2 μm and a detectivity D ≈ 10¹⁰ cm Hz^1/2/W revealing the potential of the developed device for practical applications.