Boosting Thermoelectric Power Factor of Carbon Nanotube Networks with Excluded Volume by Co-Embedded Microparticles
Boosting Thermoelectric Power Factor of Carbon Nanotube Networks with Excluded Volume by Co-Embedded Microparticles
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通过共嵌入微粒提高排除体积碳纳米管网络的热电功率因数
DOI：
10.1021/acsami.3c09136
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发表时间：
2023
影响因子：
9.5
通讯作者：
Bahk, Je-Hyeong
中科院分区：
文献类型：
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作者：
Akinboye, Oluwasegun Isaac;Zhang, Yu;Kondapalli, Vamsi Krishna;Yang, Fan;Mandrolko, Viktor;Isaiev, Mykola;Pernot, Gilles;Shanov, Vesselin;Wu, Yue;Bahk, Je-Hyeong
近年来，嵌入聚合物基体中的碳纳米管（CNT）网络作为柔性热电传输介质得到了广泛的研究。然而，它们的功率因数在很大程度上受到CNT和整个网络中的低密度导电通道之间的结处的相对低效的隧穿传输的限制。这项工作表明，显着的功率因数增强，可以通过添加电绝缘微米级颗粒嵌入在聚合物基体中的三维CNT网络。当几μm直径的二氧化硅颗粒共嵌入单壁碳纳米管（SWCNT）-聚二甲基硅氧烷（PDMS）复合材料中时，电导率和塞贝克系数同时增强，从而将功率因数提高了6倍以上。我们发现，二氧化硅微粒排除了大量的复合材料从访问的碳纳米管，并导致碳纳米管网络形成周围的聚合物作为粘合剂，从而改善网络连接和对齐的碳纳米管。我们的理论计算的基础上的结隧穿输运的三维碳纳米管网络显示，显着的功率因数的增强，可以归因于增强的隧道与减少碳纳米管之间的结距离。通过样品压缩实现了三倍的额外功率因数增强，这进一步减小了平均结距离以增强隧穿，但同时也减小了几何因子，限制了电导率的增强。
Carbon nanotube (CNT) networks embedded in a polymer matrix have been extensively studied as a flexible thermoelectric transport medium over the recent years. However, their power factor has been largely limited by the relatively inefficient tunneling transport at junctions between CNTs and the low-density conducting channels throughout the networks. This work demonstrates that significant power factor enhancements can be achieved by adding electrically insulating microscale particles in three-dimensional CNT networks embedded in the polymer matrix. When silica particles of a few μm diameters were co-embedded in single-walled CNT (SWCNT)-polydimethylsiloxane (PDMS) composites, both the electrical conductivity and the Seebeck coefficient were simultaneously enhanced, thereby boosting the power factor by more than a factor of six. We found that the silica microparticles excluded a large volume of the composite from the access of CNTs and caused CNT networks to form around them with the polymer as a binder, resulting in improved network connectivity and alignment of CNTs. Our theoretical calculations based on junction tunneling transport for three-dimensional CNT networks show that the significant power factor enhancement can be attributed to the enhanced tunneling with reduced junction distance between CNTs. Additional power factor enhancement by a factor of three was achieved by sample compression, which further reduced the mean junction distance to enhance tunneling but also reduced the geometric factor at the same time, limiting the enhancement of electrical conductivity.