Promoting p‐Type PbS as Efficient Candidates for Thermoelectric Cooling and Power Generation

Abstract Thermoelectric technology holds strategic significance in industrial residual heat recovery and solid‐state cooling. Nonetheless, the broad implementation of the mainstream Bi ₂ Te ₃ ‐based materials is hindered by tellurium's (Te) low abundance and high expenses. Herein, an economical and abundant p‐type lead sulfide (PbS) compound exhibiting remarkable thermoelectric properties is developed. By utilizing a stepwise strategy involving lattice plainification, trace elemental doping, and band engineering, the optimal p‐type polycrystal PbS exhibits a maximum ZT value of ≈1.0 at 823 K, while the crystal sample prepared via a temperature gradient method attains an unprecedented room‐temperature ZT > 0.4. A novel thermoelectric cooling device is then fabricated utilizing p‐type PbS crystal coupled with n‐type Bi ₂ (Te,Se) ₃ , which demonstrates a maximum cooling temperature difference ∆ T _max of ≈52.0 K under a hot‐side temperature of 343 K. Furthermore, an all‐PbS‐based segmented single‐leg device is constructed integrating low‐temperature crystal with high‐temperature polycrystal. This device exhibits an average ZT of ≈0.7 across a wide temperature range (300–823 K). When subjected to a 400 K temperature gradient (Δ T ), it achieves a peak efficiency of ≈8.4%. Such advancements highlight the immense potential of PbS thermoelectrics in room‐temperature cooling as well as mid‐temperature power generation.