【作者】 邓慧超；

【导师】 胡庆雷；

【作者基本信息】 哈尔滨工业大学 ， 控制科学与工程， 2010， 硕士

【摘要】 碳纳米管由于具有比表面积高、孔隙结构丰富和表面能高等特点,受到了研究人员的广泛关注。采用碳纳米管作为气敏材料的气体传感器具有高灵敏度、低响应时间和良好的稳定性等优点,具有广阔的应用前景。本文主要针对碳纳米管气敏传感器对苯系物的响应特性开展研究。由于碳纳米管薄膜具有孔状结构,苯系物气体分子能够在其中发生分子吸附以及毛细凝聚。由于苯系物气体分子的吸附,碳纳米管吸附气体后电容值随气体浓度的改变而改变,据此可以通过传感器电容的改变来测试气体浓度的改变。基于上述工作原理,选择丝网印刷工艺制备了掺杂低温玻璃粉的碳纳米管薄膜苯系物传感器。根据气体测试的要求,设计满足气密性好、浓度可控、可观察等要求的碳纳米管苯系物传感器测试装置。利用蒸镀和光刻的工艺制作出Al电极,通过丝网印刷方式制作出碳纳米管薄膜,进而制作出叉指电容式碳纳米管苯系物气敏传感器。对碳纳米管进行化学修饰,对化学修饰后的碳纳米管传感器的性能进行测试。实验结果表明,经过化学修饰可提高传感器对低浓度被测物的灵敏度和稳定性。通过测试碳纳米管苯系物传感器对不同测试频率的响应,综合考虑灵敏度和稳定性等方面因素,选定测试系统的测试频率为1kHz。以苯、甲苯、二甲苯为被测对象,对碳纳米管苯系物传感器的响应与恢复时间、重复特性、灵敏度、温度特性等性能进行测试。结果表明碳纳米管苯系物传感器具有响应速度快、重复性好等优点,而且在相同温度条件下,对二甲苯的灵敏度最高。更多还原

【Abstract】 Because of the special characteristics of large surface-volume ratio, abundant hole structure and high surface activity, carbon nanotubes (CNTs) has drawn much more attention by many researchers. They can be used as gas sensing material, so gas adsorption process with high sensitivity, fast response time and advantages of long-term stability. Thus, they exhibit broad application prospects.This article focuses on carbon nanotube gas sensor response characteristics of benzene gas. As the carbon nanotube film has a pore-like structure, benzene gas molecules can congregate due to molecular adsorption and capillary condensation. As the benzene gas molecules adsorbed, the dielectric constant of carbon nanotubes changes with the gas concentration. Thus, capacitance change of the sensor could test the gas concentration changes. Based on the above concept, we choose the screen printing to prepare carbon nanotube benzene sensor adulterated with low temperature glass power, films doped benzene sensor. With the requirements of the gas test, we design a benzene sensor test device which meets air tightness, concentration control, well observation and other requirements of the carbon nanotubes.Inter-digital capacitive benzene Multi-walled carbon nanotubes (MWNTs) sensor, whose electrode is made by evaporation and photolithography technology and the films are made by screen printing technology is introduced in this paper. By testing benzene carbon nanotube sensor in different frequencies and considering the sensitivity and stability factors, we selected the test system at a frequency of 1kHz. Characteristics of sensor’s sensitivity response time, recovery time repeatability, temperature performance are evaluated with benzene, toluene, xylene. Test results show that the benzene carbon nanotube sensor performs well. At the same temperature conditions, it is most sensitive to xylene. Finally, chemical modification of carbon nanotubes to improve sensor performance was tested for its effectiveness. The results showed that chemical modification can improve the sensor sensitivity and stability of the low concentration measured object.更多还原