Quadruple-band synglisis enables high thermoelectric efficiency in earth-abundant tin sulfide crystals
Shan Liu, Shulin Bai, Yi Wen, Jing Lou, Yongzhen Jiang, Yingcai Zhu, Dongrui Liu, Yichen Li, Haonan Shi, Shibo Liu, Lei Wang, Junqing Zheng, Zhe Zhao, Yongxin Qin, Zhongkai Liu, Xiang Gao, Bingchao Qin, Cheng Chang, Chao Chang, Li‐Dong Zhao
Abstract
Thermoelectrics have been limited by the scarcity of their constituent elements, especially telluride. The earth-abundant, wide-bandgap ( E g ≈ 46 k B T ) tin sulfide (SnS) has shown promising performance in its crystal form. We improved the thermoelectric efficiency in SnS crystals by promoting the convergence of energy and momentum of four valance bands, termed quadruple-band synglisis. We introduced more Sn vacancies to activate quadruple-band synglisis and facilitate carrier transport by inducing SnS 2 in selenium (Se)–alloyed SnS, leading to a high dimensionless figure of merit ( ZT ) of ~1.0 at 300 kelvin and an average ZT of ~1.3 at 300 to 773 kelvin in p-type SnS crystals. We further obtained an experimental efficiency of ~6.5%, and our fabricated cooler demonstrated a maximum cooling temperature difference of ~48.4 kelvin at 353 kelvin. Our observations should draw interest to earth-abundant SnS crystals for applications of waste-heat recovery and thermoelectric cooling.