Lattice Plainification Leads to High Thermoelectric Cooling Performance in Physically Vapor-Deposited N-Type PbSe Crystal

Abstract

Thermoelectric materials enable solid-state cooling, which has drawn significant attention in the electronics industry. Current thermoelectric cooling devices rely on advanced Bi₂Te₃ alloys. However, the scarcity of the Te element raises the price of thermoelectric devices and limits their widespread use. Therefore, developing high-performance, low-cost thermoelectric materials is a key focus in the field. In this work, a high-performance n-type PbSe crystal is developed through lattice plainification and physical vapor deposition. Adding trace amounts of Sn is found to compensate for intrinsic Pb vacancies, which effectively improves the crystal quality and significantly enhances the electron mobility from 1125 to 1550 cm² V⁻¹ s⁻¹. This results in a high power factor of 37 µW cm⁻¹ K⁻² at room temperature for PbSe crystal, transforming this traditional mid-temperature power generation thermoelectric material into a solid-state refrigeration material. The 7-pairs PbSe-based module achieves a temperature difference of 52 K at room temperature, demonstrating a competitive coefficient of performance (COP) of 3.5 under 5 K cooling conditions. Single-leg efficiency tests also validate a 4.5% conversion efficiency at T_h = 773 K for the material. All of these results demonstrate the practical application value of the physically vapor-deposited PbSe crystal.