Browsing by Author "Taylor, Lauren W."

Now showing 1 - 4 of 4
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    High efficiency carbon nanotube thread antennas
    (AIP Publishing, 2017) Bengio, E. Amram; Senic, Damir; Taylor, Lauren W.; Tsentalovich, Dmitri E.; Chen, Peiyu; Holloway, Christopher L.; Babakhani, Aydin; Long, Christian J.; Novotny, David R.; Booth, James C.; Orloff, Nathan D.; Pasquali, Matteo
    Although previous research has explored the underlying theory of high-frequency behavior of carbon nanotubes (CNTs) and CNT bundles for antennas, there is a gap in the literature for direct experimental measurements of radiation efficiency. These measurements are crucial for any practical application of CNT materials in wireless communication. In this letter, we report a measurement technique to accurately characterize the radiation efficiency of λ/4 monopole antennas made from the CNT thread. We measure the highest absolute values of radiation efficiency for CNT antennas of any type, matching that of copper wire. To capture the weight savings, we propose a specific radiation efficiency metric and show that these CNT antennas exceed copper's performance by over an order of magnitude at 1 GHz and 2.4 GHz. We also report direct experimental observation that, contrary to metals, the radiation efficiency of the CNT thread improves significantly at higher frequencies. These results pave the way for practical applications of CNT thread antennas, particularly in the aerospace and wearable electronics industries where weight saving is a priority.
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    Macroscopic weavable fibers of carbon nanotubes with giant thermoelectric power factor
    (Springer Nature, 2021) Komatsu, Natsumi; Ichinose, Yota; Dewey, Oliver S.; Taylor, Lauren W.; Trafford, Mitchell A.; Yomogida, Yohei; Wehmeyer, Geoff; Pasquali, Matteo; Yanagi, Kazuhiro; Kono, Junichiro; Carbon Hub
    Low-dimensional materials have recently attracted much interest as thermoelectric materials because of their charge carrier confinement leading to thermoelectric performance enhancement. Carbon nanotubes are promising candidates because of their one-dimensionality in addition to their unique advantages such as flexibility and light weight. However, preserving the large power factor of individual carbon nanotubes in macroscopic assemblies has been challenging, primarily due to poor sample morphology and a lack of proper Fermi energy tuning. Here, we report an ultrahigh value of power factor (14 ± 5 mW m−1 K−2) for macroscopic weavable fibers of aligned carbon nanotubes with ultrahigh electrical and thermal conductivity. The observed giant power factor originates from the ultrahigh electrical conductivity achieved through excellent sample morphology, combined with an enhanced Seebeck coefficient through Fermi energy tuning. We fabricate a textile thermoelectric generator based on these carbon nanotube fibers, which demonstrates high thermoelectric performance, weavability, and scalability. The giant power factor we observe make these fibers strong candidates for the emerging field of thermoelectric active cooling, which requires a large thermoelectric power factor and a large thermal conductivity at the same time.
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    Ultrahigh strength, modulus, and conductivity of graphitic fibers by macromolecular coalescence
    (AAAS, 2022) Lee, Dongju; Kim, Seo Gyun; Hong, Seungki; Madrona, Cristina; Oh, Yuna; Park, Min; Komatsu, Natsumi; Taylor, Lauren W.; Chung, Bongjin; Kim, Jungwon; Hwang, Jun Yeon; Yu, Jaesang; Lee, Dong Su; Jeong, Hyeon Su; You, Nam Ho; Kim, Nam Dong; Kim, Dae-Yoon; Lee, Heon Sang; Lee, Kun-Hong; Kono, Junichiro; Wehmeyer, Geoff; Pasquali, Matteo; Vilatela, Juan J.; Ryu, Seongwoo; Ku, Bon-Cheol; The Carbon Hub
    Theoretical considerations suggest that the strength of carbon nanotube (CNT) fibers be exceptional; however, their mechanical performance values are much lower than the theoretical values. To achieve macroscopic fibers with ultrahigh performance, we developed a method to form multidimensional nanostructures by coalescence of individual nanotubes. The highly aligned wet-spun fibers of single- or double-walled nanotube bundles were graphitized to induce nanotube collapse and multi-inner walled structures. These advanced nanostructures formed a network of interconnected, close-packed graphitic domains. Their near-perfect alignment and high longitudinal crystallinity that increased the shear strength between CNTs while retaining notable flexibility. The resulting fibers have an exceptional combination of high tensile strength (6.57 GPa), modulus (629 GPa), thermal conductivity (482 W/m·K), and electrical conductivity (2.2 MS/m), thereby overcoming the limits associated with conventional synthetic fibers.
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    Versatile acid solvents for pristine carbon nanotube assembly
    (AAAS, 2022) Headrick, Robert J.; Williams, Steven M.; Owens, Crystal E.; Taylor, Lauren W.; Dewey, Oliver S.; Ginestra, Cedric J.; Liberman, Lucy; Ya’akobi, Asia Matatyaho; Talmon, Yeshayahu; Maruyama, Benji; McKinley, Gareth H.; Hart, A. John; Pasquali, Matteo; The Smalley Institute for Nanoscale Science and Technology; The Carbon Hub
    Chlorosulfonic acid and oleum are ideal solvents for enabling the transformation of disordered carbon nanotubes (CNTs) into precise and highly functional morphologies. Currently, processing these solvents using extrusion techniques presents complications due to chemical compatibility, which constrain equipment and substrate material options. Here, we present a novel acid solvent system based on methanesulfonic or p-toluenesulfonic acids with low corrosivity, which form true solutions of CNTs at concentrations as high as 10 g/liter (≈0.7 volume %). The versatility of this solvent system is demonstrated by drop-in application to conventional manufacturing processes such as slot die coating, solution spinning continuous fibers, and 3D printing aerogels. Through continuous slot coating, we achieve state-of-the-art optoelectronic performance (83.6 %T and 14 ohm/sq) at industrially relevant production speeds. This work establishes practical and efficient means for scalable processing of CNT into advanced materials with properties suitable for a wide range of applications.