Thermal characterization of carbon nanotube fiber by time-domain differential Raman

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• 作者：Changzheng Li^a ; Shen Xu^b ; Yanan Yue^a ; ^{yyue@whu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Bing Yang^a ; Xinwei Wang^b
• 刊名：Carbon
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：103
• 期：Complete
• 页码：101-108
• 全文大小：1443 K

文摘

Most conventional Raman thermometry for thermal properties measurement is on steady-state basis, which utilizes either Joule heating effect or two lasers configurations coupled with increased complexity of system or measurement uncertainty. In this work, a new comprehensive approach including both transient and steady-state Raman method is proposed for thermal properties measurement of micro/nanowires. The transient method employs a modulated (pulsed) laser for transient heating and Raman excitation, and is termed time-domain differential Raman. The average elevated temperature during the transient heating period is probed simultaneously based on Raman thermometry. Thermal diffusivity can be readily determined by fitting normalized temperature rise against heating time with a transient heat conduction model. On the other hand, thermal conductivity can be obtained in the steady-state measurement by adjusting modulation settings. To verify this method, a carbon nanotube (CNT) fiber is measured with the thermal diffusivity of ${1.74}_{-0.20}^{+0.20}\times {10}^{-5}$ m²/s and the thermal conductivity of ${34.3}_{-0.4}^{+0.4}$ W/m K. The relatively low thermal transport values stem from numerous CNT-glue matrix and CNT–CNT thermal contact resistances. Compared with the conventional steady-state Raman method, the transient method requires no detailed laser absorption value and no temperature coefficient calibration. It can be easily applied to study transient thermal transport in materials.