Lattice Plainification Leads to High Thermoelectric Performance of P-Type PbSe Crystals.

Thermoelectrics has applications in power generation and refrigeration. Since only commercial Bi 2 Te 3 has a low abundance Te, PbSe gets attention. This work enhances the near-room temperature performance of p-type PbSe through enhancing carrier mobility via lattice plainification. Composition controlled and Cu-doped p-type PbSe crystals are grown through physical vapor deposition. Results exhibit an enhanced carrier mobility ≈2578 cm 2  V -1  s -1 for Pb 0.996 Cu 0.0004 Se. Microstructure characterization and density functional theory calculations verify the introduced Cu atoms filled Pb vacancies, realizing lattice plainification and enhancing the carrier mobility. The Pb 0.996 Cu 0.0004 Se sample achieves a power factor ≈42 µW cm -1  K -2 and a ZT ≈ 0.7 at 300 K. The average ZT of it reaches ≈0.9 (300-573 K), resulting in a single-leg power generation efficiency of 7.1% at temperature difference of 270 K, comparable to that of p-type commercial Bi 2 Te 3 . A 7-pairs device paired the p-type Pb 0.996 Cu 0.0004 Se with the n-type commercial Bi 2 Te 3 shows a maximum cooling temperature difference ≈42 K with the hot side at 300 K, ≈65% of that of the commercial Bi 2 Te 3 device. This work highlights the potential of p-type PbSe for power generation and refrigeration near room temperature and hope to inspire researchers on replacing commercial Bi 2 Te 3 .