Lattice plainification advances highly effective SnSe crystalline thermoelectrics

Thermoelectric technology has been widely used for key areas, including waste-heat recovery and solid-state cooling. We discovered tin selenide (SnSe) crystals with potential power generation and Peltier cooling performance. The extensive off-stoichiometric defects have a larger impact on the transport properties of SnSe, which motivated us to develop a lattice plainification strategy for defects engineering. We demonstrated that Cu can fill Sn vacancies to weaken defects scattering and boost carrier mobility, facilitating a power factor exceeding similar to 100 microwatts per centimeter per square kelvin and a dimensionless figure of merit (ZT) of similar to 1.5 at 300 kelvin, with an average ZT of similar to 2.2 at 300 to 773 kelvin. We further realized a single-leg efficiency of similar to 12.2% under a temperature difference (DT) of similar to 300 kelvin and a seven-pair Peltier cooling DTmax of similar to 61.2 kelvin at ambient temperature. Our observations are important for practical applications of SnSe crystals in power generation as well as electronic cooling.

Automated summary

Tin selenide (SnSe) crystals were found to have potential power generation and Peltier cooling performance. By filling Sn vacancies, the scattering of defects was weakened and the carrier mobility was boosted, resulting in a power factor exceeding 100 μW/(cm·K^2) and a figure of merit (ZT) of approximately 1.5 at 300K, with an average ZT of about 2.2 from 300 to 773K. A single-leg efficiency of about 12.2% under a temperature difference (DT) of about 300K and a seven-pair Peltier cooling DTmax of about 61.2K at ambient temperature was achieved.