Chaisitsak, Sutichai

Preferred name

Alternative Name

Chaisitsak, S.

Main Affiliation

School of Engineering

sutichai.ch@kmitl.ac.th

Now showing 1 - 10 of 11

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F-doped nanocrystalline SnO2 thin films for liquid petroleum gas (LPG) sensors
(2011-10-04)
Chaisitsak, S.
In this paper we reported the improvement sensing performance of nanocrystalline SnO<inf>2</inf> thin film based LPG sensors by doping with fluorine. Un-doped and F-doped tin oxide films were prepared on glass substrates by dip-coating technique using a layer-by-layer deposition cycle (alternating between dip-coating a thin layer followed by a drying in air after each new layer). The results showed that this technique is superior to the conventional technique for both improving the film thickness uniformity and film transparency. Atomic Force Microscopy (AFM) and X-ray diffraction pattern measurements showed that the obtained thin films were nanocrystalline SnO <inf>2</inf>. Gas sensing characteristics (sensor response, response/recovery time and repeatability) of the nanocrystalline SnO<inf>2</inf> sensors based on a planar interdigital structure were investigated at different operating temperatures and different LPG concentrations. The addition of fluorine to SnO<inf>2</inf> was found to be advantageous for efficient detection of LPG gases, e.g. F-doped sensors were more stable at low operating temperature and had higher sensor response and faster response/recovery time, compared to un-doped sensor material. © 2011 IEEE.
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Fast-LPG Sensors at Room Temperature by α -Fe2O3/CNT Nanocomposite Thin Films
(2018-01-01)
Chaitongrat, B.
;
Chaisitsak, S.
We present performance of a room temperature LPG sensor based on α-Fe2O3/CNT (carbon nanotube) nanocomposite films. The nanocomposite film was fabricated via the metallic Fe catalyst particle on CNTs in which both the catalyst particles and the CNT were simultaneously synthesized by chemical vapor deposition (CVD) synthesis and were subsequently annealed in air to create α-Fe2O3. These methods are simple, inexpensive, and suitable for large-scale production. The structure, surface morphologies, and LPG response of nanocomposite films were investigated. Raman spectroscopy and XPS analysis showed the formation of α-Fe2O3 on small CNTs (SWNTs). Morphological analysis using FE-SEM and AFM revealed the formation of the porous surface along with roughness surface. Additionally, the sensing performance of α-Fe2O3/CNTs showed that it could detect LPG concentration at lower value than 25% of LEL with response/recovery time of less than 30 seconds at room temperature. These results suggest that the α-Fe2O3/CNTs films are challenging materials for monitoring LPG operating at room temperature.
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Spray deposited CuInS2/TiO2 thin film solar cells
(2013-09-02)
Kaliang, J.
;
Chaisitsak, S.
Copper indium sulfide (CIS) solar cells with Ag/CIS/TiO<inf>2</inf>/FTO/ glass structure were fabricated by non-vacuum methods. The nanoporous TiO <inf>2</inf> and nanocrystalline CIS films were prepared by screen-printing and spray pyrolysis techniques, respectively. The obtained films were examined using field-emission scanning electron microscopy and X-ray diffraction. The solar cell properties were characterized under AM 1.5. The porous nature of TiO <inf>2</inf> layer was found to cause the formation of nanocrystalline CIS with a very small grain size within the TiO<inf>2</inf> matrix. The photocurrent could not be observed in any devices without a TiO<inf>2</inf> layer (i.e. CIS/FTO), while it was detected for the devices consisting of TiO<inf>2</inf> layer (i.e. CIS/TiO<inf>2</inf>/FTO). The thickness of TiO<inf>2</inf> layer was optimized for maximum efficiency. The highest efficiency obtained solar cells was 2.3 × 10-5 % (V<inf>oc</inf>: 0.147 V, J<inf>sc</inf>: 6.5×10-7A/cm2, FF: 0.24) with a 3-μm-thick TiO<inf>2</inf>. © 2013 IEEE.
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Novel preparation and characterization of fe2 o3 /cnt thin films for flammable gas sensors
(2019-01-01)
Chaitongrat, Buaworn
;
Chaisitsak, Sutichai
In this work, novel preparation for Fe<inf>2</inf> O<inf>3</inf> /CNT thin films was investigated. The Fe/CNT thin films were synthesized through vertical floating-catalyst chemical vapor deposition technique (FC-CVD) and subsequently annealed in air. The various annealing temperature to create Fe<inf>2</inf> O<inf>3</inf> was examined and characterized by field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), Ultraviolet–visible spectroscopy (UV-Vis) and Raman spectroscopy. In addition, effect of wet/dry process on gas sensing of Fe<inf>2</inf> O<inf>3</inf> /CNTs was also investigated. The results suggest that the interfacial oxide layer helps to significantly improve LPG sensing performance with rapid response and recovery times. The proposed method can be considered as a promising approach for producing ultra-Fe<inf>2</inf> O<inf>3</inf> /CNT thin films that are appropriate for sensing application.
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Nanocrystalline SnO2: F thin films for liquid petroleum gas sensors
(2011-07-01)
Chaisitsak, Sutichai
This paper reports the improvement in the sensing performance of nanocrystalline SnO2-based liquid petroleum gas (LPG) sensors by doping with fluorine (F). Un-doped and F-doped tin oxide films were prepared on glass substrates by the dip-coating technique using a layer-by-layer deposition cycle (alternating between dip-coating a thin layer followed by a drying in air after each new layer). The results showed that this technique is superior to the conventional technique for both improving the film thickness uniformity and film transparency. The effect of F concentration on the structural, surface morphological and LPG sensing properties of the SnO<inf>2</inf> films was investigated. Atomic Force Microscopy (AFM) and X-ray diffraction pattern measurements showed that the obtained thin films are nanocrystalline SnO<inf>2</inf> with nanoscale-textured surfaces. Gas sensing characteristics (sensor response and response/recovery time) of the SnO2:F sensors based on a planar interdigital structure were investigated at different operating temperatures and at different LPG concentrations. The addition of fluorine to SnO<inf>2</inf> was found to be advantageous for efficient detection of LPG gases, e.g., F-doped sensors are more stable at a low operating temperature (300 °C) with higher sensor response and faster response/recovery time, compared to un-doped sensor materials. The sensors based on SnO2:F films could detect LPG even at a low level of 25% LEL, showing the possibility of using this transparent material for LPG leak detection. © 2011 by the authors.
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Effects of three parameters on graphene synthesis by chemical vapor deposition
(2013-09-02)
Dathbun, Ajjiporn
;
Chaisitsak, Sutichai
A high quality graphene film on a copper foil was successfully grown by a CVD process using ethanol as a carbon source. The effect of growth temperatures (650-850°C), reaction times (5-50 min) and post-CVD cooling process rates (slow-cooling, fast-cooling and fast-cooling under ethanol exposure) on the formation of graphenes was investigated by Raman spectroscopy and scanning electron microscopy (SEM). The graphene film deposited under the optimal conditions showed features of a high quality such as a high I <inf>2D</inf>/I<inf>G</inf> ratio of ∼8, a low I<inf>D</inf>/I<inf>G</inf> ratio of 0.28 and a narrow full width half maximum (FWHM) of Lorentzian-shaped 2D peak of ∼35 cm-1. It was found that the quality of graphene film could be enhanced by optimizing the growth temperature and time, while the number of graphene layer was less sensitive to the cooling rate. However, the fast cooling process under ethanol exposure was found to be a key process for obtaining graphenes with a large domain size. These findings may help to fabricate high-quality graphenes on a copper foil for electronic applications. © 2013 IEEE.
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Antibacterial activity and nanocomposite properties of monodispersed silver nanoparticles synthesized by the microwave method
(2016-01-01)
Lothongkum, Anchaleeporn W.
;
Wongparb, Kornwika
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Sethapokin, Pinthep
;
Chaisitsak, Sutichai
Monodispersed colloidal silver nanoparticles (Ag-NPs) were synthesized by a simple and rapid microwave method. A precursor, AgNO<inf>3</inf>, was reduced by ethylene glycol (EG) and N,N-dimethylformamide (DMF) in the presence of polyvinylpyrrolidone (PVP) as a stabilizer or capping agent. It was found that the concentration of AgNO<inf>3</inf> significantly affected Ag-NPs particle sizes. The particle sizes decreased when the concentration decreased from 0.1 to 0.05 and 0.01 M, which corresponded to narrow size distribution of the particle diameters of approximately 60 to 80, 30 to 40 and 10 to 20 nm. The spherical-shaped monodispersed Ag-NPs were obtained by using a volume ratio of EG to DMF of 2.75:2.25, microwave power of 400 W and heating time of 2 min. The volume ratio of EG to DMF and the microwave power influenced the uniformity of the Ag-NPs shape and size, while the heating time had no effect. For antibacterial application, 60-80 and 10-20 nm Ag-NPs showed good disinfection ability against Escherichia coli (ATCC 25922) at the minimum inhibitory concentrations (MIC) of 32 and 16 (μg × ml-1, respectively. In addition, the electrical resistance of the nanocomposites of DMF-loaded Ag-NPs (20-50 nm) without PVP on single-walled carbon nanotubes and polyethylene terephthalate (PET) was measured. As a result, it is obvious that the Ag-NPs help to increase the electrical conductivity of the nanocomposites as the electrical resistance of the Ag-NPs nanocomposites was 4.68 kΩ × cm-2 compared to that of the nanocomposites without Ag-NPs of 8.76 kΩ × cm-2.
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Fabrication of SWNTs/α-Fe2O3 as room-temperature LPG sensor
(2015-12-31)
Chaitongrat, Buaworn
;
Chaisitsak, Sutichai
A simple fabrication of liquid petroleum gas sensor based on SWNTs/α-Fe2O3 nanocomposite films is reported. SWNTs/α-Fe2O3 films were successfully synthesized through the vertical floating catalyst chemical vapor deposition method using ferrocene-ethanol mist, followed by annealing in air at 350 oC to create α-Fe2O3. To fabricate a sensor, carbon conductive electrodes were directly deposited on top of the SWNTs/α-Fe2O3 films. SWNTs/α-Fe2O3 growth conditions (deposition time and ferrocene/ethanol ratio) were optimized to improve sensor response. The sensor had the capability to detect LPG at a concentration as low as 0.2% LEL (lower explosive limit), indicating possible applications in LPG monitoring 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/cm2 and an 80% transmittance at the wavelength of 550 nm after nitric acid treatment.
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Hybrid Fe2O3/CNT thin films for gas sensor applications
(2018-08-13)
Chaitongrat, Buaworn
;
Chaisitsak, Sutichai
Thin films of Fe nanoparticles (NPs)/CNT networks were synthesized through vertical floating catalyst chemical vapor deposition technique (FC-CVD) and collected directly onto a cellulose membrane filter. Fe NPs/CNT films were transferred onto glass (or Si) substrates simply by dissolving filters, and then annealed in air at a low temperature for 8 hrs to create Fe<inf>2</inf>O<inf>3</inf> NPs. The effect of annealing temperature ranging from 150 to 550°C on the morphology and structures of the Fe<inf>2</inf>O<inf>3</inf>/CNTs films was investigated by field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), differential thermal analysis (DTA), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Fe<inf>2</inf>O<inf>3</inf>/CNTs film-based sensors were tested against LPG gas under room temperature. LPG sensing-performance (sensor response and response/recovery time) of the Fe<inf>2</inf>O<inf>3</inf>/CNTs films-based sensor varied depending on the annealing temperature. The results of this study reinforce the potential of hybrid Fe<inf>2</inf>O<inf>3</inf>/CNTs films as a sensing material for LPG detection at low operating temperature.

Chaisitsak, Sutichai

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