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

Pengyingkai Wang; Yongjia Zheng; Taiki Inoue; Rong Xiang; Ahmed Shawky; Makoto Watanabe; Anton Anisimov; Esko I Kauppinen; Shohei Chiashi; Shigeo Maruyama

doi:10.1021/acsnano.9b09754

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

ACS Nano. 2020 Apr 28;14(4):4298-4305. doi: 10.1021/acsnano.9b09754. Epub 2020 Apr 16.

Authors

Pengyingkai Wang¹, Yongjia Zheng¹, Taiki Inoue¹, Rong Xiang¹, Ahmed Shawky^{1

2}, Makoto Watanabe¹, Anton Anisimov³, Esko I Kauppinen⁴, Shohei Chiashi¹, Shigeo Maruyama^{1

5}

Affiliations

¹ Department of Mechanical Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
² Nanomaterials and Nanotechnology Department, Advanced Materials Division, Central Metallurgical R&D Institute (CMRDI), P.O. Box 87 Helwan, Cairo 11421, Egypt.
³ Canatu, Ltd., Konalankuja 5, Helsinki FI-00390, Finland.
⁴ Department of Applied Physics, Aalto University School of Science, 15100, Aalto FI-00076, Finland.
⁵ Energy NanoEngineering Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba 305-8654, Japan.

PMID: 32271541
DOI: 10.1021/acsnano.9b09754

Abstract

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: boron nitride nanotube; chemical vapor deposition; in-plane sheet thermal conductance; infrared thermography; single-walled carbon nanotube film; van der Waals heterostructure.