Pecharapa, Wisanu

Preferred name

Pecharapa, Wisanu

Alternative Name

PECHARAPA, Wisanu

Pecharapa, W.

Main Affiliation

Integrated Innovative Technology

wisanu.pe@kmitl.ac.th

Now showing 1 - 10 of 16

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Characterization of Sol-gel derived Ti-doped tungsten oxide electrochromic thin films
(2011-01-01)
Paipitak, K.
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Kahattha, C.
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Techitdheera, W.
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Porntheeraphat, S.
;
Pecharapa, W.
Ti-doped WO<inf>3</inf> electrochromic thin films were deposited onto F-doped tin oxide (FTO) substrates using spin coating technique. The as-deposited films prepared with various concentration of titanium were annealed in air at 500°C. The effect of Ti-doping concentration on structural, surface morphology and optical properties of the films were characterized by X-ray diffractometer, scanning electron microscope and UV-VIS spectrophotometer. The results show that the crystalline of WO<inf>3</inf> can be identified at 2θ values of 24.14° corresponding to 200 orientation. In addition, It was found that the electrochromic performance of WO<inf>3</inf> can be enhanced by small doping concentration of titanium due to structural modification of the films. © 2011 Published by Elsevier Ltd.
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Physical properties of Ti-doped ITO nanoparticles synthesized by co-precipitation method
(2016-04-26)
Chongsri, K.
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Kanoksinwuttipong, J.
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Techitdheera, W.
;
Pecharapa, W.
Ti-doped indium tin oxide (ITO) nanoparticles (TITO) with different molar ratios of Ti:ITO were synthesized by co-precipitation method using Ti(OCH2CH2CH2CH3)4, InCl3 and SnCl4·5H2O as starting precursors. Deionized (DI) water was selected as the solvent in this process. The as-precipitated powders were calcined at different temperature in range of 700 °C for 2 h. For all samples, their crystal structures, Optical property and morphologies were investigated by X-ray diffraction (XRD), UV-Vis absorption spectroscopy and Scanning electron microscope (SEM), respectively. XRD results reveal that the purity of as-synthesized sample is increased by the increase of calcination temperatures. Moreover, it is noticed that the incorporation of Ti into ITO matrix significantly affects to their relevant physical properties especially optical properties. In addition, SEM micrographs show that the sample agglomeration is noticeably influenced by Ti doping content.
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Characterization and phase formation study of ZnO:Sn nanoparticles synthesized by co-precipitation method
(2014-09-02)
Noonuruk, R.
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Mekprasart, W.
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Supparattanasamai, T.
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Kanyapan, T.
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Techitdheera, W.
ZnO:Sn were successfully prepared by co-precipitation method using zinc acetate dihydrate and tin (IV) chloride hexahydrate as host and dopant precursor sources, respectively. The ratio of Sn doping content in ZnO was designated at 0, 5, 10 and 20 wt.% and calcined at different temperatures at 200, 300, 400 and 500°C. Physical properties and composition of Sn-doped ZnO powder were monitored by X-ray diffraction and scanning electron microscope. Chemical bonding of as-synthesized powders were investigated by Fourier transform spectroscopy. The preliminary results indicate that the crystallinity and morphologies of ZnO nanoparticle are significantly affected by Sn dopant. The phase formation of Zn-Sn-O was observed depending on the Sn-doping composition and calcination temperature. Meanwhile, FTIR results indicate the existence of mixture phases of ZnO:Sn in the compounds which were obtained via precipitation process. © 2014 Taylor & Francis Group, LLC.
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Characterisation of Ti-doped indium tin oxide nanoparticles synthesised by co-precipitation process
(2016-01-01)
Chongsri, K.
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Kanoksinwuttipong, J.
;
Techitdheera, W.
;
Pecharapa, W.
Ti-doped indium tin oxide (ITO) nanoparticles (TITO) with different molar ratios of Ti:ITO were synthesised by co-precipitation method using Ti(OCH<inf>2</inf>CH<inf>2</inf>CH<inf>2</inf>CH<inf>3</inf>)<inf>4</inf>, InCl<inf>3</inf> and SnCl<inf>4</inf>·5H<inf>2</inf>O as starting precursors. Deionised (DI) water was selected as the solvent in this process. The as-precipitated powders were calcined at different temperatures around 700°C for 2 h. For all samples, their crystal structures, optical properties and morphologies were investigated by X-ray diffraction (XRD), UV-Vis absorption spectroscopy, scanning electron microscope (SEM), and transmission electron microscope (TEM), respectively. XRD results reveal that the purity of as-synthesised samples is increased with the increase of calcination temperatures. Relevant mechanisms involved in the synthesis via precipitation process are discussed. It is noticed that the incorporation of Ti into ITO matrix significantly affects the relevant physical properties and optical properties.
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Ozone-induced optical density change of NiO thin films and their applicability as neutral optical density filter
(2011-05-02)
Noonuruk, R.
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Wongpisutpaisan, N.
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Mukdacharoenchai, P.
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Techitdheera, W.
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Pecharapa, W.
Nickel oxide (NiO) thin films were deposited onto glass substrates by sol-gel spin-coating technique. The coating solution was prepared by reacting nickel acetate tetrahydrate as precursor and absolute ethanol as solvent. The asdeposited films were annealed in air at 350oC. The color of the film can be changed from bleach color to be dark brownish after UV/ozone treatment. The change in optical density of more than 40% can be achieved after 5 min of treatment. The colored films can be readily recovered by thermal treatment at 150°C within 30 min. Further increasing ozone exposure time leads to greater change in optical density. The presence of ozone-induced hydroxyl groups causes the color change of the films. The unique behavior of this chromic material can be applied as novel tunable neutral optical density filters and related devices by ozone-assisted method.
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Influence of gas source supply interruption on quantum well structure of few monolayer InP/In0.53Ga0.47As/InP grown by OMVPE
(2002-01-01)
Pecharapa, W.
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Techitdheera, W.
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Nukeaw, J.
A model of asymmetric stepped quantum well affected by gas source supply interruption at the interface of extremely thin InP/In<inf>0.53</inf>Ga<inf>0.47</inf>As/InP single quantum well grown by Organometallic Vapor Phase Epitaxy (OMVPE) is developed. The energy levels in the well and the intersubband transition energies are carried out and compared to experimental data from photoreflectance spectroscopy.
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Titanium dioxide/Vanadium oxide nanocomposites synthesized via sonochemical and hydrothermal process for energy storage application
(2013-03-13)
Kahattha, C.
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Techitdheera, W.
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Vittayakorn, N.
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Pecharapa, W.
V<inf>2</inf>O<inf>5</inf>/TiO<inf>2</inf> nanocomposites were synthesized via sonochemical and hydrothermal process. At first, titanium dioxide (TiO <inf>2</inf>) nanopowders were synthesized by sonochemical process using titanium isopropoxide as a titanium source. Meanwhile, hydrothermal process was carried out to modify the structure of commercial V<inf>2</inf>O<inf>5</inf> powder to be nanorod-like structure V<inf>2</inf>O<inf>5</inf> with increasing specific surface area. Structural and morphological properties of the composites were characterized by XRD and SEM, respectively. The XRD results indicated that the crystalline of the composites corresponds to anatase and orthorhombic structures of TiO<inf>2</inf> and V<inf>2</inf>O<inf>5</inf>, respectively. The significant variation of charge storage properties of the nanocomposites under ultraviolet irradiation were obtained by varying V<inf>2</inf>O<inf>5</inf> content in the composite. Results suggest that V<inf>2</inf>O<inf>5</inf> loaded into the nanocomposite play a key role as a storage material of photoelectron generated by TiO<inf>2</inf> illuminated under ultraviolet. © 2013 IEEE.
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Preparation, characterisation and photocurrent study of sol-gel-derived Al, Mg-doped ZnO transparent thin films
(2014-01-01)
Chongsri, K.
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Techitdheera, W.
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Pecharapa, W.
In this work, sol-gel spin-coating was employed to prepare ZnO, Al-doped ZnO (AZO) and Mg-doped ZnO (MZO) thin films onto glass substrates. Structural properties and surface morphologies of as-prepared films were characterised by X-ray diffraction (XRD) and scanning electron microscope (SEM) while their optical properties were scrutinised from their transmission spectra measured by UV-VIS spectrophotometer. Their optical responses and sensitivity of the films were investigated by photocurrent spectroscopy. The XRD and SEM results show that the crystallinity and physical structure of as-prepared films are highly affected by Al and Mg doping. UV-VIS spectrophotometer results suggest that Mg and Al dopants could not only improve their optical transparency but also significantly cause the blue-shift in optical band gap of ZnO films. In addition, the enhancement in photosensitivity of ZnO films can be attained by specific Al and Mg doping content. Copyright © 2014 Inderscience Enterprises Ltd.
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Characterization and photocurrent study of Al, Mg-doped ZnO transparent thin films prepared by sol-gel route
(2013-03-13)
Techitdheera, W.
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Chongsri, K.
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Pecharapa, W.
In this work, ZnO, Al-doped ZnO (AZO) and Mg-doped ZnO (MZO) thin films were deposited onto glass substrates by sol-gel spin-coating method. The doping composition was varied from 0-10 at.%. Structural properties and surface morphologies of as-prepared films were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). Optical properties of the films were interpreted from their transmission spectra using UV-VIS spectrophotometer. The photocurrent spectroscopy was employed to study their optical response and sensitivity of the films. The XRD and SEM results disclosed that the crystallinity and grain size of as-prepared films were strongly influenced by Al and Mg doping. UV-VIS spectrophotometer results indicated that Mg and Al additives could not only efficiently improve the optical transparency but also obviously induce the blue-shift in optical band gap of ZnO films. The photocurrents of as-prepared films disclosed that the enhancement in photosensitivity of ZnO films can be achieved by specific content of either Al or Mg additives. © 2013 IEEE.
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Investigation of milling time on particle size reduction and photoinduced activity performance of commercial TiO2 for optical energy harvesting applications
(2013-09-18)
Rattanarak, J.
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Mekprasart, W.
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Pecharapa, W.
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Techitdheera, W.
In this research, effect of milling time on crucial physical structures of commercial TiO2 powders in form of anatase phase is investigated. The as-received commercial TiO2 powders were ball-milled with ethanol solvent at room temperature at various operating time ranging from 6-24 hrs. Particle sizes and surface areas of milled powders were characterized by particle analyzer and Brunauer Emmet Teller (BET) method.TiO2 surface morphologies of the powders milled at various times were monitored by scanning electron microscope. The photocatalytic activities of the milled powders were conducted by mean of the photo-induced degradation against RhB aqueous solution. The results reveal that particle size of the commercial TiO2 powders can be effectively minimized to few hundred nanometer range depending on milling time. The drastic reduction in their size results to the increasing active surface area of the particles and the enhanced photo-induced activity that was supported by the photodegradation performance. This enhancement can suggest them to the suitability in optical energy harvesting optoelectronic applications including photovoltaic devices, optical based sensors and related environmental-friendly usage. © 2013 SPIE.

Pecharapa, Wisanu

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