SWCNT nano-composite optical sensors for VOC and gas trace detection

Abstract The feasibility of exploiting novel chemo-sensitive coatings based on cadmium arachidate (CdA)/single-walled carbon nanotube (SWCNT) composites for the development of high performance optical chemo-sensors has been experimentally investigated and proved. SWCNT nano-composite overlays have been transferred on the distal end of standard optical fibers by the Langmuir–Blodgett deposition technique in order to realize extrinsic low-finesse Fabry-Perot interferometers. A structural and morphological characterization of the fabricated optical probes has been carried out by scanning electron microscopy observations and Raman spectroscopy analysis. Reflectance measurements have been carried out to test the sensing performance of the proposed devices to volatile organic compound (VOC) and gas exposure. Also, VOC trace detection has been evaluated in different environments, such as air and water. Obtained results have also been compared in the same operating conditions to those obtained in the case of standard SWCNT overlays deposited by using the same deposition technique and optical transducers in order to outline the effect of the nano-composite matrix both on the material integration effectiveness and sensing performance. The results shown here demonstrate that the use of nano-composite coatings not only promotes a better adhesion of the sensitive overlay to the fiber surface, thus improving the robustness of the chemo-optical sensors, but also significantly enhances their sensitivities from three to seven times with respect to the SWCNT overlay directly deposited on the fiber surface. Moreover, resolutions in the range 30–250 part per billion (ppb) and 0.6–1.5 part per million (ppm) have been estimated in case of air and water environments, respectively.

[1]  Antonello Cutolo,et al.  Carbon nanotube acoustic and optical sensors for volatile organic compound detection , 2005 .

[2]  A. Vaseashta,et al.  Nanostructured and nanoscale devices, sensors and detectors , 2005 .

[3]  Craig A. Grimes,et al.  Gas sensing characteristics of multi-wall carbon nanotubes , 2001 .

[4]  M. Consales,et al.  Carbon Nanotubes Coated Acoustic and Optical VOCs Sensors: Towards the Tailoring of the Sensing Performances , 2007, IEEE Transactions on Nanotechnology.

[5]  W. D. Kingery,et al.  Introduction to Ceramics , 1976 .

[6]  H. Macleod,et al.  Thin-Film Optical Filters , 1969 .

[7]  J. Stetter,et al.  Theoretical basis for identification and measurement of air contaminants using an array of sensors having partly overlapping selectivities , 1984 .

[8]  Joo-Hiuk Son,et al.  Terahertz absorption and dispersion of fluorine-doped single-walled carbon nanotube , 2005 .

[9]  M. Penza,et al.  Sensing properties of buffered and not buffered carbon nanotubes by fibre optic and acoustic sensors , 2006 .

[10]  Jose Maria Kenny,et al.  Sensors for inorganic vapor detection based on carbon nanotubes and poly(o-anisidine) nanocomposite material , 2004 .

[11]  Michele Penza,et al.  Carbon nanotubes as SAW chemical sensors materials , 2004 .

[12]  Vijay K. Varadan,et al.  Carbon nanotube/PMMA composite thin films for gas-sensing applications , 2003 .

[13]  Michele Penza,et al.  Single-walled carbon nanotubes nanocomposite microacoustic organic vapor sensors , 2006 .

[14]  H. K. Heinrich,et al.  Picosecond noninvasive optical detection of internal electrical signals in flip-chip-mounted silicon integrated circuits , 1990 .

[15]  K. Balasubramanian,et al.  Chemically functionalized carbon nanotubes. , 2005, Small.

[16]  T. Someya,et al.  Alcohol Vapor Sensors Based on Single-Walled Carbon Nanotube Field Effect Transistors , 2003 .

[17]  M. Consales,et al.  Chemical Detection in Water by Single-Walled Carbon Nanotubes-Based Optical Fiber Sensors , 2007, IEEE Sensors Journal.

[18]  David A. Jackson,et al.  Recent progress in monomode fibre-optic sensors , 1994 .

[19]  Wojtek Wlodarski,et al.  Layered SAW gas sensor with single-walled carbon nanotube-based nanocomposite coating , 2007 .

[20]  A. Di Carlo,et al.  Gas sensing using single wall carbon nanotubes ordered with dielectrophoresis , 2005 .

[21]  S. D. Collins,et al.  A micromachined pressure sensor with fiber-optic interferometric readout , 1994 .

[22]  Michele Penza,et al.  Carbon nanotubes-based surface acoustic waves oscillating sensor for vapour detection , 2005 .

[23]  Kong,et al.  Nanotube molecular wires as chemical sensors , 2000, Science.

[24]  Hiromichi Kataura,et al.  Gas adsorption in the inside and outside of single-walled carbon nanotubes , 2001 .

[25]  Antonello Cutolo,et al.  Alcohol detection using carbon nanotubes acoustic and optical sensors , 2004 .

[26]  A. Kersey,et al.  Applications of fiber-optic sensors , 1989 .

[27]  Jose Maria Kenny,et al.  Sensors for sub-ppm NO2 gas detection based on carbon nanotube thin films , 2003 .

[28]  Lynn Fuller,et al.  A chemical sensor for chloromethanes using a nanocomposite of multiwalled carbon nanotubes with poly(3-methylthiophene) , 2005 .

[29]  I. Gentle,et al.  The structures of Langmuir-Blodgett films of fatty acids and their salts. , 2001, Advances in colloid and interface science.

[30]  Vikram Joshi,et al.  Nanoelectronic Carbon Dioxide Sensors , 2004 .

[31]  Joo-Hiuk Son,et al.  Optical and electrical properties of preferentially anisotropic single-walled carbon-nanotube films in terahertz region , 2004 .

[32]  Bin Zhang,et al.  Preparation and characterization of gas-sensitive composites from multi-walled carbon nanotubes/polystyrene , 2005 .

[33]  R. Wu,et al.  The application of CNT/Nafion composite material to low humidity sensing measurement , 2005 .

[34]  G. Roberts,et al.  Langmuir-Blodgett films , 1984 .

[35]  F. Wooten,et al.  Optical Properties of Solids , 1972 .

[36]  M. Dresselhaus,et al.  Physical properties of carbon nanotubes , 1998 .

[37]  Yang-Kyu Choi,et al.  Chemical sensors based on nanostructured materials , 2007 .

[38]  Seung Yol Jeong,et al.  Enhanced Sensitivity of a Gas Sensor Incorporating Single‐Walled Carbon Nanotube–Polypyrrole Nanocomposites , 2004 .

[39]  Saurabh Chopra,et al.  Selective gas detection using a carbon nanotube sensor , 2003 .

[40]  R. Soref,et al.  Electrooptical effects in silicon , 1987 .