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Hybrid gas sensor based on platinum nanoparticles/poly(methyl methacrylate)-coated single-walled carbon nanotubes for dichloromethane detection with a high response magnitude
(2016-05-01)
Muangrat, Worawut
;
Yordsri, Visittapong
;
Maolanon, Rungroj
;
Pratontep, Sirapat
;
Porntheeraphat, Supanit
A dichloromethane (DCM) sensor with a high response magnitude was successfully fabricated using the integration of single-walled carbon nanotubes (SWNTs), poly(methyl methacrylate) (PMMA) and platinum nanoparticles (Pt NPs). A pristine SWNT network was first formed by drop-casting onto printed circuit board (PCB) substrates. Next, PMMA was coated onto the pre-dropped SWNT network by spin coating using a PMMA-toluene solution, followed by the deposition of Pt NPs by electron-beam evaporation (hereafter referred to as Pt/PMMA/SWNT). The Pt/PMMA/SWNT enabled an approximately 69-fold improvement in DCM detection compared to pristine SWNT. The high response magnitude of the Pt/PMMA/SWNT was successfully achieved because of the incorporation of PMMA and Pt functions. Swelling of the PMMA matrix as a result of DCM adsorption leads to PMMA volume expansion, thereby increasing the SWNT-SWNT distance, which results in an increase in the resistance. Pt NPs promote the dissociation of DCM to CO, and consequently the CO oxidation on the Pt NPs catalyst and electron donation from Pt NPs to SWNTs, resulting in an increase in the resistance. Moreover, a linear relationship was obtained between the sensor response of the Pt/PMMA/SWNT and the concentration of DCM. These results suggest that the integration of SWNTs with PMMA and Pt NPs is a promising approach for improving DCM detection at room temperature.
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Ferrocene-ethanol-mist CVD grown SWCNT films as transparent electrodes
(2014-01-01)
Jantharamatsakarn, Kittipong
;
Chaisitsak, Sutichai
The floating catalyst CVD using ferrocene-ethanol mist was successfully used to deposit single-walled carbon nanotube (SWCNT) films from the gaseous phase onto a Si substrate and a membrane filter. The home-built vertical mist-CVD system was used without the use of H<inf>2</inf> or CO gases. The tiny mist was generated using a high-frequency ultrasonic vibration. The effects of various parameters including furnace temperature, ferrocene/ethanol ratio, the deposition position in the reactor, flow rate of carrier gas, and deposition time on the SWCNTs formation were investigated using SEM, TEM and Raman spectroscopy. The furnace temperature and the flow rate of carrier gas were found to determine the diameter and crystallinity of nanotubes. The ferrocene concentration in ethanol influenced the diameter distribution of nanotubes and the amount of impurity particles in the materials. The collected SWCNT films on a filter were directly transferred to a laminate sheet by using a hot press laminator. The properties of SWCNTs were investigated by UV-Vis spectrophotometer and four-point probe measurement. The high sheet resistance was observed for the as-transferred films. However, the initial results show that a sheet resistance of 10 kΩ/cm<sup>2</sup> and an 80% transmittance at the wavelength of 550 nm after nitric acid treatment.
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Ferrocene-ethanol-mist CVD grown SWCNT films as transparent electrodes
(2014-01-01)
Jantharamatsakarn, Kittipong
;
Chaisitsak, Sutichai
The floating catalyst CVD using ferrocene-ethanol mist was successfully used to deposit single-walled carbon nanotube (SWCNT) films from the gaseous phase onto a Si substrate and a membrane filter. The home-built vertical mist-CVD system was used without the use of H2 or CO gases. The tiny mist was generated using a high-frequency ultrasonic vibration. The effects of various parameters including furnace temperature, ferrocene/ethanol ratio, the deposition position in the reactor, flow rate of carrier gas, and deposition time on the SWCNTs formation were investigated using SEM, TEM and Raman spectroscopy. The furnace temperature and the flow rate of carrier gas were found to determine the diameter and crystallinity of nanotubes. The ferrocene concentration in ethanol influenced the diameter distribution of nanotubes and the amount of impurity particles in the materials. The collected SWCNT films on a filter were directly transferred to a laminate sheet by using a hot press laminator. The properties of SWCNTs were investigated by UV-Vis spectrophotometer and four-point probe measurement. The high sheet resistance was observed for the as-transferred films. However, the initial results show that a sheet resistance of 10 kΩ/cm<sup>2</sup> and an 80% transmittance at the wavelength of 550 nm after nitric acid treatment.
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Adsorption kinetics of NO2 on single-walled carbon nanotube thin-film sensor
(2008-10-01)
Wongwiriyapan, Winadda
;
Inoue, Satoshi
;
Honda, Shin ichi
;
Katayama, Mitsuhiro
The adsorption kinetics of NO<inf>2</inf> on a single-walled carbon nanotube (SWNT) thin-film sensor was investigated. To avoid the influence of ambient air, the adsorption property of SWNTs was explored under high vacuum. By virtue of the suppression of the influence of residual gases and the cleanness of the SWNT surface in vacuum, the SWNTs exhibited high sensitivity with a detection limit of lower than 1 ppb. On the basis of the Langmuir adsorption isotherm, the sticking probability and adsorption energy of NO<inf>2</inf> molecules on SWNTs were experimentally estimated. © 2008 The Japan Society of Applied Physics.
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