Temperature Distribution and Thermal Conductivity\nMeasurements of Chirality-Assigned Single-Walled Carbon Nanotubes\nby Photoluminescence Imaging Spectroscopy

Abstract

It is expected that\nsingle-walled carbon nanotubes (SWCNTs) have\nhigh thermal conductivity along the tube axis and that the thermal\nconductivities depend on their structure, such as length, diameter,\nchirality (<i>n</i>, <i>m</i>), and so forth.\nAlthough many experimental measurements of the thermal conductivity\nhave been reported, the SWCNT structure was not characterized sufficiently.\nIn particular, the chirality was not assigned, and it was not confirmed\nwhether SWCNT was isolated or not (bundled with multiplicate SWCNTs).\nTherefore, measured values widely vary (10¹ to 10⁴ W/(m·K)) so far. Here, we measured the thermal conductivity\nof chirality-assigned SWCNTs, which were individually suspended, by\nusing photoluminescence (PL) imaging spectroscopy. The temperature\ndistribution along the tube axis was obtained, and the temperature\ndependence of the thermal conductivity was measured in a wide-temperature\nrange (from 350 to 1000 K). For (9, 8) SWCNTs with 10–12 μm\nin length, the thermal conductivity was 1166 ± 243 W/(m·K)\nat 400 K. The proposed PL imaging spectroscopy enables to measure\nthe thermal conductivity of SWCNTs with high precision and without\nany contacts, and it is an effective method in the temperature distribution\nmeasurements of nanomaterials.