Thermoelectric power generation, allowing recovery of part of the energy wasted as heat, is emerging as an important component of renewable energy and energy efficiency portfolios. Although inorganic semiconductors have traditionally been employed in thermoelectric applications, organic semiconductors garner increasing attention as versatile thermoelectric materials. Here we present a combined theoretical and experimental study suggesting that semiconducting single-walled carbon nanotubes with carefully controlled chirality distribution and carrier density are capable of large thermoelectric power factors, higher than 340 μW m^-1 K^-2, comparable to the best-performing conducting polymers and larger than previously observed for carbon nanotube films. Furthermore, we demonstrate that phonons are the dominant source of thermal conductivity in the networks, and that our carrier doping process significantly reduces the thermal conductivity relative to undoped networks. These findings provide the scientific underpinning for improved functional organic thermoelectric composites with carbon nanotube inclusions.

http://www.nature.com/articles/nenergy201633

热电材料可以将热能转化为电能，因此正逐渐成为一种重要的能源回收手段。尽管一直以来热电材料都是基于无机材料，但最近有机半导体材料也逐渐开始受到科学家们的关注。Avery等人用理论计算和实验相结合的手段发现，通过精细控制手性分布和载流子密度，半导体单壁碳纳米管网络也可以获得很高的功率因子，其值可与当前最好的导电聚合物相媲美。同时，他们还发现，网络结构中声子是主要的导热源，不过通过掺杂可以有效降低热导率。这些发现为开发有机热电材料提供了打下了很好的基础。（Nature Energy DOI: 10.1038/NENERGY.2016.33）