Carbon Nanotube Thin Films Functionalized via Loading of Au Nanoclusters for Flexible Gas Sensors Devices

Abstract

Carbon nanotubes (CNTs) have been demonstrated to be one of the most interesting materials for gas sensing. This paper applies a simple method for the direct transfer of highdensity CNTs from a SiO 2 /Si substrate to a flexible substrate for carbon dioxide (CO 2 ), ammonia (NH 3 ), and isopropyl alcohol gas sensing at room temperature. The flexible gas sensor exhibited high sensitivities of 4.8%, 5.4%, and 5.2% at room temperature for ambient CO 2 , NH 3 , and isopropyl alcohol gas concentrations of 800 ppm, respectively. In addition, the gas response of the CNT-based chemiresistor is attributed to p-type conductivity in the Au-modified semiconducting CNTs. Very good repeatability of the sensor response to gas concentration is demonstrated, representing a major step toward the low-cost large-scale production of this class of device.Index Terms-Carbon nanotube (CNT), flexible, gas sensor.

Vapor-phase impregnation decomposition technique as an alternativeto decorate MWCNTs withPt and PdNPs for ammonia gas detection

“…From the table above, we infer that our values of sensitivity (41-171.5) for the sensor containing Pt/MWCNTs (at 250 • C) are much higher than these previously reported in literature (0.025-10) for CNT based systems decorated with other metallic NPs. According to Young and Lin et al [16,17], Au NPs can give a range of sensitivity from 1.1 to 2.74%. Other cases, such as Ag/MWCNT sensors reported by Nguyen et al [14] and Cui et al [19] showed a sensitivity of 9% at room temperature.…”

“…MWCNTs decorated with Pt-Ag NPs showed up to 5% more sensitivity than the MWCNTs without NPs, which have only 1.5%. Nanoparticles such as Au, Pt [15][16][17] SnO 2 [18], Ag [14,19], Co [20], ITO [21], Ag/ polyaniline [22] Pd [23] and CdS [10] have been also used on MWCNTs, for ammonia gas detection. So far, techniques such as electron beam evaporation, plasma treatment, sputtering coating, precipitation from the metal salt solution, and thermal evaporation have been employed to decorate MWCNTs [15][16][17][18][19][20][21][22][23].…”

“…Nanoparticles such as Au, Pt [15][16][17] SnO 2 [18], Ag [14,19], Co [20], ITO [21], Ag/ polyaniline [22] Pd [23] and CdS [10] have been also used on MWCNTs, for ammonia gas detection. So far, techniques such as electron beam evaporation, plasma treatment, sputtering coating, precipitation from the metal salt solution, and thermal evaporation have been employed to decorate MWCNTs [15][16][17][18][19][20][21][22][23]. Even though interesting efforts have been made to increase sensitivity and selectivity on MWCNTs, it remains a constant need to find better techniques to gain a large response with a lower response and recovery times.…”

Tuning Coating Thickness of Iron Tetraphenyl Porphyrin on Single Walled Carbon Nanotubes by Annealing: Effect on Benzene Sensing Performance

“…Hegde et al has recently reported a high surface area TiO 2 nanotube array sensor that had lowest detection limit of 100 ppm. In line with standard protocol of validating reproducibility/reversibility characteristics of the sensor, the same was subjected to cycles of three repeated exposure at 100 ppm (fourfold of the represented validation maximum limit) concentration of benzene. The sensor exhibited excellent reversibility as shown in Figure (b; inset) and no sign of response degradation/baseline drift could be observed.…”

Carbon‐nanotube‐loaded planar gas and humidity sensor

“…The sensor was designed at 2.4 GHz so that it can be easily compatible with Wi‐Fi and Bluetooth devices, and the sensor geometry can be easily scaled to other frequencies. The design can be also fabricated on low cost substrates such as the work by Lin et al, 18 and can be integrated with new engineering methods to improve the sensitivity of CNT film, 19 for further improved sensing capability.…”