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

Abstract

Thermoelectrics has applications in power generation and refrigeration. Since only commercial Bi2 Te3 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 ≈2578cm2 V-1 s-1 for Pb0.996 Cu0.0004 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 Pb0.996 Cu0.0004 Se sample achieves a power factor ≈42µWcm-1 K-2 and a ZT ≈ 0.7 at 300K. The average ZT of it reaches ≈0.9 (300-573K), resulting in a single-leg power generation efficiency of 7.1% at temperature difference of 270K, comparable to that of p-type commercial Bi2 Te3 . A 7-pairs device paired the p-type Pb0.996 Cu0.0004 Se with the n-type commercial Bi2 Te3 shows a maximum cooling temperature difference ≈42K with the hot side at 300K, ≈65% of that of the commercial Bi2 Te3 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 Bi2 Te3 .