Najeeb Choolakadavil Khalid, Lee Jae-Hyoek, Chang Jingbo, Kang Won-Seok, Kim Jae-Ho
Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea.
J Nanosci Nanotechnol. 2009 Dec;9(12):6928-33. doi: 10.1166/jnn.2009.1619.
Single-walled carbon nanotube (SWNT)/Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS), composites (SWNT/PEDOT-PSS) have been prepared using SWNTs surface modified with a natural gum, 'gum arabic' by simple mixing process. Thin films of SWNTs, PEDOT-PSS and the composites were prepared by vacuum filtration technique and were exposed to ultraviolet (UV) radiations for photoconductivity measurements. The surface resistivity of pristine SWNTs film increased from initial value of 50 omega to 92 omega and that of the polymer film decreased from 6.7 Komega to 3.1 Komega while the resistivity of the composite film decreased from 267 omega to 232 omega upon UV illumination. When the lamp was switched off, the initial resistivities of PEDOT: PSS and SWNTs films were recovered very slowly. Interestingly, on the other hand the composite films demonstrated a very fast relaxation within a few minutes. An on-off cycle ruled out the possibility of local heating effect and revealed that the switching property was originated from the fast transport of charge and heat in the composite films. This property of composite film might open up optoelectronic applications involving photoconductivity, such as photo sensors, organic light emitting diodes (OLED) and organic solar cells. Here in, we demonstrate the application of the SWNT/PEDOT-PSS composite film based device as a UV sensor.
通过简单的混合工艺，利用经天然树胶“阿拉伯树胶”表面改性的单壁碳纳米管（SWNT）制备了单壁碳纳米管/聚（3,4-乙撑二氧噻吩）-聚（苯乙烯磺酸盐）（PEDOT-PSS）复合材料（SWNT/PEDOT-PSS）。通过真空过滤技术制备了SWNT、PEDOT-PSS及其复合材料的薄膜，并将其暴露于紫外线（UV）辐射下进行光电导率测量。原始SWNT薄膜的表面电阻率从初始值50Ω增加到92Ω，聚合物薄膜的表面电阻率从6.7KΩ降低到3.1KΩ，而复合薄膜的电阻率在紫外线照射下从267Ω降低到232Ω。当灯关闭时，PEDOT:PSS和SWNT薄膜的初始电阻率恢复得非常缓慢。有趣的是，另一方面，复合薄膜在几分钟内表现出非常快速的弛豫。开-关循环排除了局部热效应的可能性，并表明开关特性源于复合薄膜中电荷和热量的快速传输。复合薄膜的这种特性可能会开启涉及光电导率的光电子应用，如光电传感器、有机发光二极管（OLED）和有机太阳能电池。在此，我们展示了基于SWNT/PEDOT-PSS复合薄膜的器件作为紫外线传感器的应用。
