▲ 作者:SHAN LIU, SHULIN BAI, YI WEN, JING LOU, YONGZHEN JIANG, YINGCAI ZHU, ET AL.
▲ 链接:
https://www.science.org/doi/10.1126/science.ado1133
▲ 摘要:
热电材料一直受到其组成元素稀缺的限制,尤其是碲化物。地球上储量丰富的宽禁带(Eg≈46 kBT)硫化锡(SnS)在晶体形态上表现出颇具前景的性能。
研究组通过促进四个价带的能量和动量辐合来提高SnS晶体的热电效率,称为四能带合成。他们在硒(Se)合金SnS中引入了更多的Sn空位来激活四能带合成,并通过诱导SnS2来促进载流子的传输,从而实现p型SnS晶体在300 K温度下约1.0的高无量纲品质系数(ZT),在300 K~ 773 K温度下的平均ZT为1.3。
研究组进一步获得了6.5%的实验效率,其制造的冷却器在353 K时的最大冷却温差为48.4 K。该发现有望引起人们对地球上储量丰富的SnS晶体在废热回收和热电冷却方面应用的兴趣。
▲ Abstract:
Thermoelectrics have been limited by the scarcity of their constituent elements, especially telluride. The earth-abundant, wide-bandgap (Eg ≈ 46 kBT) 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 fo
ur valance bands, termed quadruple-band synglisis. We introduced more Sn vacancies to activate quadruple-band synglisis and facilitate carrier transport by inducing SnS2 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.