High room-temperature thermoelectric performance is important for low-grade waste heat power generation as there are plenty of heat thrown away uselessly in our daily life, most of which are below 100 °C. However, most of the thermoelectric materials are limited to high temperature application. In this work, room-temperature thermoelectric power factor of carbon nanotube (CNT) yarn is improved by controlled doping, which is achieved by making composite with poly 3-hexylthiophene −2, 5-diyl (P3HT) followed by doping with 2, 3, 5, 6-tetrafluo-7, 7, 8, 8-tetracyanoquinodimethane (F4TCNQ). The temperature-dependent Seebeck coefficient based on power–law model suggests that P3HT shifts the Fermi energy of CNT yarn towards the valence band edge, and reduces the ionic scattering and carrier relaxation time. As a result, the Seebeck coefficient is increased while the variation of Seebeck coefficient with temperature is reduced, and hence, the room-temperature thermoelectric power factor is improved. With controlled doping, the power factor of CNT yarn/P3HT composite reaches to 1640–2160 μW m⁻¹K⁻² at the temperature range of 25–100 °C, which is higher than that of CNT yarn alone.

室温高的热电性能对于低等级的余热发电非常重要，因为在我们的日常生活中有大量无用的热量被浪费掉，其中大部分温度低于100°C。但是，大多数热电材料仅限于高温应用。在这项工作中，通过控制掺杂来改善碳纳米管（CNT）纱线的室温热电功率因数，这是通过与聚3-己基噻吩-2，5-二基（P3HT）进行复合，然后掺杂2，3来实现的，5、6-四氟-7、7、8、8-四氰基喹二甲烷（F4TCNQ）。基于幂律模型的温度依赖性塞贝克系数表明，P3HT将CNT纱线的费米能移向价带边缘，并减少了离子散射和载流子弛豫时间。结果是，塞贝克系数增加，而塞贝克系数随温度的变化减小，因此，改善了室温热电功率因数。通过控制掺杂，CNT纱线/ P3HT复合材料的功率因数达到1640–2160μWm 在25–100°C的温度范围内^-1 K ^-2，这比仅CNT纱线的温度高。