Li Qin-Yi, Liu Jin-Hui, Wang Hai-Dong, Zhang Xing, Takahashi Koji
Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China.
Rev Sci Instrum. 2013 Oct;84(10):104905. doi: 10.1063/1.4824494.
Optical absorptance is an important property of carbon nanotubes for practical applications but has rarely been accurately measured. We developed a T type thermal probe method to measure the optical absorptance of an individual multiwall carbon nanotube. In this method, one end of the carbon nanotube (CNT) is attached to the center of a platinum nanofilm in a T shape and the Pt nanofilm acts as a thermometer. A laser beam irradiates at the CNT and the absorbed laser power can be determined by measuring the average temperature rise of the Pt nanofilm based on the temperature dependence of the electric resistance. Experimental results showed that a 100-nm-diameter multiwall CNT could absorb 13.2% of the 514-nm-wavelength laser power with the laser spot diameter being 1 μm. This method is useful for determining the optical absorptance of CNTs and other one-dimensional nanostructures such as Si/Ge nanowires for various optical wavelengths in their photovoltaic, photoelectrolysis and other optical applications.
光吸收率是碳纳米管在实际应用中的一个重要特性，但很少被精确测量。我们开发了一种T型热探针方法来测量单个多壁碳纳米管的光吸收率。在这种方法中，碳纳米管（CNT）的一端以T形连接到铂纳米薄膜的中心，铂纳米薄膜充当温度计。激光束照射在碳纳米管上，基于电阻对温度的依赖性，通过测量铂纳米薄膜的平均温度上升可以确定吸收的激光功率。实验结果表明，直径为100纳米的多壁碳纳米管在激光光斑直径为1微米时，可以吸收514纳米波长激光功率的13.2%。这种方法对于确定碳纳米管和其他一维纳米结构（如硅/锗纳米线）在其光伏、光电解和其他光学应用中各种光波长下的光吸收率很有用。
