Photo-electronic Hybrids Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.
Nanoscale. 2019 Sep 19;11(36):16919-16927. doi: 10.1039/c9nr05757a.
With the increase in practical interest in flexible thermoelectric (TE) generators, the demand for high-performance alternatives to brittle TE materials is growing. Herein, we have demonstrated wet-spun CNT fibers with high TE performance by systematically controlling the longitudinal carrier mobility without a significant change in the carrier concentration. The carrier mobility optimized by CNT alignment increases the electrical conductivity without decreasing the thermopower, thus improving the power factor. On further adjusting the charge carriers via mild annealing, the CNT fibers exhibit a high power factor of 432 μW m-1 K-2. Based on the excellent TE performance and shape advantages for modular design of the CNT fiber, the all-carbon based flexible TE generator without an additional metal electrode has been fabricated. The flexible TE generator based on 40 pairs of p- and n-type CNT fibers shows the maximum power density of 15.4 and 259 μW g-1 at temperature differences (ΔT) of 5 and 20 K, respectively, currently one of the highest values reported for TE generators based on flexible materials. The strategy proposed here can improve the performance of flexible TE fibers by optimizing the carrier mobility without a change in the carrier concentration, and shows great potential for flexible TE generators.
随着人们对柔性热电（TE）发电机实际应用兴趣的增加，对替代易碎 TE 材料的高性能替代品的需求也在不断增长。在此，我们通过系统地控制纵向载流子迁移率，在不显著改变载流子浓度的情况下，展示了具有高 TE 性能的湿纺 CNT 纤维。通过 CNT 排列优化的载流子迁移率提高了电导率，而不会降低热功率，从而提高了功率因数。通过进一步通过温和退火来调整电荷载流子，CNT 纤维表现出 432 μW m-1 K-2 的高功率因数。基于 CNT 纤维的优异 TE 性能和模块化设计的形状优势，已经制造了没有额外金属电极的全碳基柔性 TE 发电机。基于 40 对 p 型和 n 型 CNT 纤维的柔性 TE 发电机在温差（ΔT）为 5 和 20 K 时的最大功率密度分别为 15.4 和 259 μW g-1，这是目前基于柔性材料的 TE 发电机中报道的最高值之一。这里提出的策略可以通过优化载流子迁移率而不改变载流子浓度来提高柔性 TE 纤维的性能，为柔性 TE 发电机展示了巨大的潜力。
