Most of the thermoelectric research, these days, is being focussed towards development of flexible thermoelectric power generators (TEG) for wearable applications. Organic thermoelectric materials being flexible and solution processable, though, seem promising cannot render themselves for designing of conventional thermoelectric devices which require both p- and n-type of legs; due to lack of air-stable and flexible n-type materials. This work shows the possibility of conversion of a p-type flexible free-standing multiwalled carbon nanotubes (MWCNTs) paper into n-type on treatment with polyethylenimine (PEI). X-ray photoelectron spectroscopy results suggest that ‘as-grown’ MWCNTs attained n-type nature due to electron donation by imine group of PEI. Power factors of ~0.2 and ~0.06 μW/mK² observed respectively for p- and n-type MWCNTs papers, owing to extremely low thermal conductivity (~0.05W/mK), resulted in figure-of-merit (ZT) of 1.27 × 10⁻³ and 3.02 × 10⁻⁴ at 68 °C. A prototype TEG designed using ‘as-grown’ and ‘PEI-modified’ MWCNTs as p- and n-type thermoelements respectively exhibited output of 227 μV/7.6 μA for a temperature difference of 40 °C. In short, facile scalability of MWCNTs when collaborated with such a low cost, environment friendly method that can easily modify its conduction to n-type can certainly open opportunities for scalable production of flexible roll-to-roll type wearable thermoelectric modules.

如今，大多数热电研究都集中在针对可穿戴应用的柔性热电发电机（TEG）的开发上。然而，有机热电材料具有柔韧性和可溶液加工性，似乎有希望不能用于需要p型和n型支脚的常规热电设备的设计中。由于缺乏空气稳定和灵活的n型材料。这项工作表明，在用聚乙烯亚胺（PEI）处理后，p型柔性自立式多壁碳纳米管（MWCNTs）纸可能转化为n型。X射线光电子能谱结果表明，由于PEI亚胺基团给电子，“生长中”的MWCNT达到了n型性质。功率因数〜0.2和〜0.06μW/ mK ²由于极低的热导率（〜0.05W / mK），分别在p型和n型MWCNTs纸上观察到的结果导致品质因数（ZT） 在68时为1.27×10 ^-3和3.02×10 ^-4 ℃。使用“生长中的”和“ PEI修饰的” MWCNT作为p型和n型热敏元件设计的TEG原型分别在40°C的温差下显示出227μV/ 7.6μA的输出。简而言之，当与这样的低成本，环境友好的方法配合使用时，MWCNT的简便可扩展性可以轻松地将其导电性修改为n型，这无疑为可伸缩卷对卷型可穿戴热电模块的可扩展生产打开了机遇。