Advancing N-Type PbSe as Promising Candidates for Thermoelectric Cooling and Power Generation

PbSe crystals exhibit significant potential for development in thermoelectric cooling and power generation applications due to their high-ranged thermoelectric performance. Herein, we achieve lattice plainification in n-type PbSe crystals through Ge doping and additional Ge incorporation, leading to a ZT value of 0.7 at room temperature in n-type Pb_0.993Ge_0.007Se+0.0015Ge crystals. The 7-pair thermoelectric cooling device constructed by n-type Pb_0.993Ge_0.007Se+0.0015Ge crystals and p-type Bi₂Te₃ alloys attains a peak temperature difference of 66.3 K with the hot-side temperature of 343 K. Furthermore, the introduction of interstitial Cu enables a broad-temperature-range enhancement of thermoelectric performance. A high average ZT value of 1.07 can be obtained in Pb_0.993Ge_0.007Se+0.0015Ge+0.0012Cu crystal across the 303–673 K, as well as a single-leg device exhibits a peak power generation efficiency of 8.7% under the temperature gradient of 423 K. This study elucidates the great potential of n-type PbSe crystals in both thermoelectric cooling and power generation, thereby significantly advancing the practical implementation of this cost-effective thermoelectric material.