Abstract
Crystalline thermoelectrics have been developed to be potential candidates for power generation and electronic cooling, among which SnSe crystals are becoming the most representative. Herein, we realize high-performance SnSe crystals with promising efficiency through a structural modulation strategy. By alloying strontium at Sn sites, we modify the crystal structure and facilitate the multiband synglisis in p-type SnSe, favoring the optimization of interactive parameters μ and m(*). Resultantly, we obtain a significantly enhanced PF ~85 μW cm(-1) K(-2), with an ultrahigh ZT ~1.4 at 300 K and ZT(ave) ~2.0 among 300-673 K. Moreover, the excellent properties lead to single-leg device efficiency of ~8.9% under a temperature difference ΔT ~300 K, showing superiority among the current low- to mid-temperature thermoelectrics, with an enhanced cooling ΔT(max) of ~50.4 K in the 7-pair thermoelectric device. Our study further advances p-type SnSe crystals for practical waste heat recovery and electronic cooling.