Rational primary structure design for boosting the thermoelectric properties of semiconducting carbon nanotube networks

Komoto, Junichi; Goto, Chigusa; Kawai, Tsuyoshi; Nonoguchi, Yoshiyuki

doi:10.1063/5.0055640

Cited by 12 publications

(12 citation statements)

References 38 publications

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“…Numerous CNTs have been prepared using various manufacturing methods, resulting in a wide range of absolute S values, tube diameters, and numbers of semiconducting components. [49][50][51] In addition, the large CNT surface area can cause unexpected chemical doping by residual molecules during the processing of CNTs with organic solvents, which can significantly alter their S values, thereby determining their charge-carrier type. 21,39 In this study, single-walled CNTs (purity > 90%, diameter = 1.5 ± 0.8 nm, metalsemiconductor ratio = 1:2) of known elementary properties were used.…”

Section: Resultsmentioning

confidence: 99%

Water‐resistant organic thermoelectric generator with >10 μW output

et al. 2022

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Flexible p–n thermoelectric generator (TEG) technology has rapidly advanced with power enhancement and size reduction. To achieve a stable power supply and highly efficient energy conversion, absolute chemical stability of n‐type materials is essential to ensuring large temperature differences between device terminals and ambient stability. With the aim of improving the long‐term stability of the n‐type operation of carbon nanotubes (CNTs) in air and water, this study uses cationic surfactants, such as octylene‐1,8‐bis(dimethyldodecylammonium bromide) (12–8–12), a gemini surfactant, to stabilize the nanotubes in a coating, which retains the n‐doped state for more than 28 days after exposure to air and water in experiments. TEGs with 10 p–n units of 12–8–12/CNT (n‐type) and sodium dodecylbenzene sulfonate/CNT (p‐type) layers are manufactured, and their water stability is evaluated. The initial maximum output of 16.1 µW (75 K temperature difference) is retained after water immersion for 40 days without using a sealant to prevent TEG module degradation. The excellent stability of these CNT‐based TEGs makes them suitable for underwater applications, such as battery‐free health monitoring and information gathering systems, and facilitates the development of soft electronics.

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Section: Resultsmentioning

confidence: 99%

Water‐resistant organic thermoelectric generator with >10 μW output

et al. 2022

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“…To utilize CNTs on the TE devices, many conventional studies have focused on the film-state devices, − possibly due to the easiness in fabrication and characterization. However, the solution process for spinning the CNT yarn is advantageous for the mass production of flexible and stretchable modules. , To achieve a higher TE performance with CNT yarns, various strategies to form composites with many materials such as organic (e.g., poly(3,4-ethylene dioxythiophene) polystyrene sulfonate, poly(ethylenimine), etc.)…”

Section: Introductionmentioning

confidence: 99%

Carbon Nanotube/Biomolecule Composite Yarn for Wearable Thermoelectric Applications

Cho

Okamoto

Yamamoto

et al. 2022

ACS Appl. Energy Mater.

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In this work, yarn made of a hybrid material of carbon nanotubes (CNTs) and artificial biomolecules is created for the wearable thermoelectric (TE) module. Among the limited methods due to the sensitivity of proteins, the co-use of the ionic liquid and polymeric surfactant with the dialysis method is found to be effective for the dispersion of the CNT/biomolecule composite with a low CNT loss rate and high coverage by biomolecules on the CNT. This new method improved the TE performance by decreasing the bundle diameter of the CNT/C-Dps nanocomposite and better tensile strength. The incorporation of a biomolecule, in particular, significantly reduced the thermal conductivity of CNT yarns, demonstrating that the hybrid composite is advantageous for wearable device applications. This method also outperformed the conventional dispersion against the pristine CNT yarn (without protein), demonstrating the application’s generality. Finally, a low-density testing of the TE module using the CNT/biomolecule composite is demonstrated, exhibiting the output power of 4.37 μW m–2 with a thermoelectric voltage of 4.5 mV at a temperature difference of 20 K. The output power density and voltage can be easily increased 500-fold by increasing the density of the yarn and the number of series connections. This study proposes a practical method for producing an environment-friendly CNT/biomolecule hybrid yarn, which has the potential to be useful in future wearable TE applications.

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“…In recent years, flexible thermoelectric materials and devices based on carbon nanomaterials have found potential applications in power supplies for wearable electronic devices. − Compared to inorganic thermoelectric materials such as Bi and Te compounds, carbon nanotubes have the advantages of being abundant, nontoxic, easy to manufacture, quite flexible, and lightweight and exhibiting high electrical conductivity. − In particular, single-walled carbon nanotubes (SWCNTs) have received more and more attention due to their inherent high Seebeck coefficient ( S ) and excellent electrical conductivity (σ), which are important parameters for improving the conversion efficiency of thermoelectric materials. − SWCNTs are essentially n-type materials. However, SWCNTs show a p-type behavior due to the presence of oxygen and H 2 O in the air. − Compared to that of p-type SWCNTs, the development of n-type SWCNTs lags behind due to poor air stability and a difficult doping process .…”

Section: Introductionmentioning

confidence: 99%

Enhancement Effect of the C₆₀ Derivative on the Thermoelectric Properties of n-Type Single-Walled Carbon Nanotube-Based Films

Xia

Tian

Xian-Yu

et al. 2022

ACS Appl. Mater. Interfaces

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Obtaining air-stable and high-performance flexible n-type single-walled carbon nanotube (SWCNT)-based thermoelectric films used in wearable electronic devices is a challenge. In this work, the microstructure and thermoelectric properties of n-type SWCNTbased films have been optimized via doping C 60 and its derivative into polyethylenimine/ single-walled carbon nanotube (PEI/SWCNT) films. The result demonstrated that the dispersity of triethylene glycol-modified C 60 (TEG-C 60 ) was better in PEI/SWCNT films than that of pure C 60 . Among the prepared composite films, TEG-C 60 -doped PEI/SWCNT (TEG-C 60 /PEI/SWCNT) films exhibited the highest TE performance, achieving a peak electrical conductivity of 923 S cm −1 with a Seebeck coefficient of −42 μV K −1 at a TEG-C 60 /SWCNT mass ratio of 1:100. Compared to that of PEI/SWCNT, the power factor was increased significantly from 40 to 162 μW m −1 K −2 after the addition of TEG-C 60 , which was higher than that of films after the addition of C 60 . In addition, the n-type doped SWCNT films had good air stability at high temperatures, and the Seebeck coefficients of C 60 /PEI/SWCNT and TEG-C 60 /PEI/SWCNT at 120 °C were still negative and remained at 92% and 85%, respectively, after 20 days. Furthermore, a flexible TE device consisting of five pairs of p−n junctions was assembled using the optimum hybrid film, which generated a maximum output power of 3.6 μW at a temperature gradient of 50.2 K. Therefore, this study provides a facile way to enhance the thermoelectric properties of n-type carbon nanotube-based materials, which have potential application in flexible power generators.

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Rational primary structure design for boosting the thermoelectric properties of semiconducting carbon nanotube networks

Cited by 12 publications

References 38 publications

Water‐resistant organic thermoelectric generator with >10 μW output

Water‐resistant organic thermoelectric generator with >10 μW output

Carbon Nanotube/Biomolecule Composite Yarn for Wearable Thermoelectric Applications

Enhancement Effect of the C₆₀ Derivative on the Thermoelectric Properties of n-Type Single-Walled Carbon Nanotube-Based Films

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Rational primary structure design for boosting the thermoelectric properties of semiconducting carbon nanotube networks

Cited by 12 publications

References 38 publications

Water‐resistant organic thermoelectric generator with >10 μW output

Water‐resistant organic thermoelectric generator with >10 μW output

Carbon Nanotube/Biomolecule Composite Yarn for Wearable Thermoelectric Applications

Enhancement Effect of the C60 Derivative on the Thermoelectric Properties of n-Type Single-Walled Carbon Nanotube-Based Films

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Enhancement Effect of the C₆₀ Derivative on the Thermoelectric Properties of n-Type Single-Walled Carbon Nanotube-Based Films