Cost‐Effective Symmetric PbSe‐Based Device for Thermoelectric Cooling

Thermoelectric cooling technology has broad applications but is limited by the high cost of tellurium (Te) in commercially available Bi₂Te₃-based thermoelectric materials. Herein, a cost-effective symmetric PbSe-based device constructed from 7 pairs of Pb_0.988Cu_0.002Se (p-type) and Pb_1.02Cu_0.002Se (n-type) is presented, which demonstrates impressive cooling temperature difference (ΔT_C) of 32.8 and 41.0 K with the hot side maintained at 303 and 343 K, respectively. This low-cost symmetric PbSe-based device exhibits superior cost-effectiveness (ΔT/cost) for near-room-temperature thermoelectric cooling compared to other Bi₂Te₃-based devices. Its high cooling performance primarily stems from an advanced carrier and phonon transport properties in p-type Pb_0.988Cu_0.002Se. Specifically, Pb vacancy and Cu substitution in Pb_0.988Cu_0.002Se act as strong p-type dopants that effectively optimize carrier density, resulting in a maximum power factor of 28.69 µW cm^-1 K^-2 at room temperature. Moreover, the mobile Cu atoms within the lattice significantly impede phonon propagation, leading to a low room-temperature lattice thermal conductivity of 1.10 W m^-1 K^-1. Finally, the room-temperature figure of merit (ZT) and average ZT value in p-type Pb_0.988Cu_0.002Se can reach 0.6 and 0.68 at 300-573 K, surpassing previous p-type PbSe-based polycrystals. This work emphasizes the significant potential of a cost-effective PbSe compound for near-room-temperature cooling applications.