Morphology dependence of the thermal transport properties of single-walled carbon nanotube thin films

Yoshida, Shinzo; Feng, Ya; Delacou, Clement; Inoue, Taiki; Xiang, Rong; Kometani, Reo; Chiashi, Shohei; Kauppinen, Esko I.; Maruyama, Shigeo

doi:10.1088/1361-6528/aa6698

Cited by 11 publications

(11 citation statements)

References 36 publications

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“…The inplane thermal conductivity of SWNT sheets varied within two orders of magnitude in the literatures as summarized in Table S3. Therefore, the difference of the thermal conductivity range between our results (9.16-17.9 W m −1 K −1 ) and reported values (80-370 W m −1 K −1 ) was probably due to the difference of either SWNT diameter [53], length [54,55], bundle size [56], anisotropy [57,58], defect density [43], mass density [59] of SWNTs or measurement accuracy [42,[60][61][62]. We also recognized that the s-SWNT sheets had lower thermal conductivity than that of the unsorted SWNT sheet.…”

Section: Te Properties Of S-swnt Sheetscontrasting

confidence: 71%

Thermoelectric properties of sorted semiconducting single-walled carbon nanotube sheets

Huang

Tokunaga

Nakashima

et al. 2019

Science and Technology of Advanced Materials

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Single-walled carbon nanotubes (SWNTs), especially their semiconducting type, are promising thermoelectric (TE) materials due to their high Seebeck coefficient. In this study, the in-plane Seebeck coefficient ( S ), electrical conductivity ( σ ), and thermal conductivity ( κ ) of sorted semiconducting SWNT (s-SWNT) free-standing sheets with different s-SWNT purities are measured to determine the figure of merit ZT. We find that the ZT value of the sheets increases with increasing s-SWNT purity, mainly due to an increase in Seebeck coefficient while the thermal conductivity remaining constant, which experimentally proved the superiority of the high purity s-SWNT as TE materials for the first time. In addition, from the comparison between sorted and unsorted SWNT sheets, it is recognized that the difference of ZT between unsorted SWNT and high-purity s-SWNT sheet is not remarkable, which suggests the control of carrier density is necessary to further clarify the superiority of SWNT sorting for TE applications.

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Section: Te Properties Of S-swnt Sheetscontrasting

confidence: 71%

Thermoelectric properties of sorted semiconducting single-walled carbon nanotube sheets

Huang

Tokunaga

Nakashima

et al. 2019

Science and Technology of Advanced Materials

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“…Therefore, instead of thermal conductance, the product of thermal conductivity and thickness, called sheet thermal conductance, was used, which is also commonly used in other studies. 36 The Sheet Thermal Conductance of Pristine and Annealed SWCNT Films. The first step for CVD growth of BNNT is a heating step, and during this procedure, the suspended SWCNT template film first undergoes an annealing process at 1075 °C for 1 h. When annealed, a common phenomenon for CNT films, arrays, fibers, and mats is that CNTs tend to approach each other and form bundles, and the number of intertube contacts increases considerably.…”

Section: Resultsmentioning

confidence: 99%

Enhanced In-Plane Thermal Conductance of Thin Films Composed of Coaxially Combined Single-Walled Carbon Nanotubes and Boron Nitride Nanotubes

et al. 2020

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Carbon nanotubes (CNTs) and boron nitride nanotubes (BNNTs) are one-dimensional materials with high thermal conductivity and similar crystal structures. Additionally, BNNTs feature higher thermal stability in air than CNTs. In this work, a single-walled carbon nanotube (SWCNT) film was used as a template to synthesize a BNNT coating by the chemical vapor deposition (CVD) method to form a coaxial heterostructure. Then, a contact-free steady-state infrared (IR) method was adopted to measure the in-plane sheet thermal conductance of the as-synthesized film. The heterostructured SWCNT− BNNT film demonstrates an enhanced sheet thermal conductance compared with the bare SWCNT film. The increase in sheet thermal conductance shows a reverse relationship with SWCNT film transparency. An enhancement of over 80% (from ∼3.6 to ∼6.4 μW•K −1 •sq −1 ) is attained when the BNNT coating is applied to an SWCNT film with a transparency of 87%. This increase is achieved by BNNTs serving as an additional thermal conducting path. The relationship between the thermal conductance increase and transparency of the SWCNT film is studied by a structured modeling of the SWCNT film. We also discuss the effect of annealing on the thermal conductance of SWCNTs before BNNT growth. Along with the preservation of high electrical conductance, the enhanced thermal conductance of the heterostructured SWCNT−BNNT films makes them a promising building block for thermal and optoelectronic applications. KEYWORDS: single-walled carbon nanotube film, boron nitride nanotube, van der Waals heterostructure, in-plane sheet thermal conductance, chemical vapor deposition, infrared thermography

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“…As well as the IR measurement, Raman spectroscopy was also conducted to explore the thermal properties of the same four SWNT thin films [23], which are denoted by the red dots in Figure 7. The trend of the Raman results is the same as that of the IR measurements, but the values are 1.9 to 2.5 times lower.…”

Section: Resultsmentioning

confidence: 99%

Measurement of in-plane sheet thermal conductance of single-walled carbon nanotube thin films by steady-state infrared thermography

Feng¹,

Inoue²,

Watanabe³

et al. 2018

Jpn. J. Appl. Phys.

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A useful and rapid method for measuring the in-plane sheet thermal conductance of single-walled carbon nanotube (SWNT) thin films by steady-state infrared thermography is proposed in this study. The SWNT thin films are suspended between the free ends of two cantilevered silicon thin plates, and the two anchored ends are kept at different but constant temperatures to achieve steady-state heat transfer through this silicon-SWNT-silicon bridge in vacuum. The temperature gradient along the bridge is captured with an infrared camera. A silicon plate with known thermal conductivity acts as a reference to calculate the heat flux, so that the sheet thermal conductance of SWNT thin films can be calculated using Fourier's law after deducting the influence of thermal radiation. The thermal conductivity of the 50 nm thick SWNT thin film is 68.1 W m −1 K −1 .

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Morphology dependence of the thermal transport properties of single-walled carbon nanotube thin films

Cited by 11 publications

References 36 publications

Thermoelectric properties of sorted semiconducting single-walled carbon nanotube sheets

Thermoelectric properties of sorted semiconducting single-walled carbon nanotube sheets

Enhanced In-Plane Thermal Conductance of Thin Films Composed of Coaxially Combined Single-Walled Carbon Nanotubes and Boron Nitride Nanotubes

Measurement of in-plane sheet thermal conductance of single-walled carbon nanotube thin films by steady-state infrared thermography

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