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Indium Tin Oxide conductive nanoparticles synthesized by sonochemical method
(2016-10-12)
Noonuruk, Russameeruk
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Kanoksinwuttipong, Jiruntanin
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Mekprasart, Wanichaya
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Techitdheera, Wicharn
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Sritharathikhun, Jaran
This work reports the synthesis of Indium Tin Oxide (ITO) nanoparticles via sonochemical process at various calcination temperature using InCl<inf>3</inf> and SnCl<inf>4</inf>·5H<inf>2</inf>O as starting precursors for In and Sn sources, respectively. The crystal structure properties of the samples were investigated by X-ray diffraction. Meanwhile, the size, shape and microstructure of the particles were observed by field emission scanning electron microscope and chemical composition was investigated by energy dispersive X-ray Spectrophotometer. The corresponding optical band gap was determined by diffuse reflectance spectra. The XRD results showed that the as-prepared powders were initially formed in amorphous phase and the crystalline structure of powders were obtained after calcination beyond specific temperature. The correlated reactions and mechanisms during sonochemical process responsible for ITO formation are suggested. The comparison between ITO powders prepared by sonochemical process and co-precipitation process is additionally carried out and the results show significant differences in their morphology and crystallite sizes of the particles.
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Physical and optical properties of indium oxide:tin nanoparticles synthesized by co-precipitation method
(2015-01-01)
Kanoksinwuttipong, Jiruntanin
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Pecharapa, Wisanu
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Noonuruk, Russameeruk
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Techitdheera, Wicharn
Indium oxide:tin nanoparticles were synthesized by co-precipitation method using InCl<inf>3</inf> and SnCl<inf>4</inf>·5H<inf>2</inf>O as starting precursor with different molar ratios of Sn:In. The crystalline structure, optical properties, chemical bonding and morphologies of all samples were characterized by X-ray diffraction (XRD), UV-vis spectrometer, Raman spectroscopy and field emission scanning electron microscope, respectively. The XRD results show that the crystallinity of as-synthesized powders was initially amorphous phase. After calcination at 400 °C for 2 h, a single phase ITO powder with 10% (mol%) SnO<inf>2</inf> was obtained. The particle size of each sample is approximately 20-25 nm. The color of indium oxide:tin nanopowders after heat treatment changed from white to yellow due to the substitution of oxygen vacancies in the sample. After calcination, the intensity of Raman peak significantly decreased with increasing amount of Sn loading. This phenomenon indicates that ion substitution may occur during the synthesis process. Moreover, it is noticed that the optical absorbance of obviously changed with increasing Sn loading.
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Synthesis and characterization of thermochromic la 0.75 Ca 0.25MnO3 perovskite manganites nano-powders by microwave-assisted solution combustion synthesis
(2014-01-02)
Kahatta, Sagulthai
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Techitdheera, Wicharn
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Chaiyo, Nopsiri
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Pecharapa, Wisanu
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Vittayakorn, Naratip
The microwave-assisted solution combustion synthesis was developed for application with initially synthesized thermochromic perovskite manganese oxide La0.75Ca0.25MnO<inf>3</inf> nano-powders. Dry and very fine powders were obtained after one-step combustion reaction for less than 10 min in a modified domestic microwave oven. The thermal behavior, phase formation and purity of the precursor, and as-synthesized and calcined powders, were investigated by TGA/DTA, X-ray diffraction (XRD) and FT-IR techniques. The morphology of the powder obtained was characterized using a scanning electron microscope (SEM). The XRD pattern and FT-IR results showed that as-synthesized La <inf>0.75</inf>Ca<inf>0.25</inf>MnO<inf>3</inf> powders were crystalline, and the monophasic perovskite phase occurred with an average crystallite size of 30.46 ± 5.54 nm for 6 h at a relatively low calcination temperature of 900°C. The small particle size obtained by SEM suggested a high specific surface area and high sinterability. This method was found to be simple, rapid and cheap, and an effective way to prepare nano-size perovskite powders. © 2014 Taylor and Francis Group, LLC.
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Influence of milling time, NH3 additive and annealing temperature on physical properties of modified commercial TiO2 powders via ball milling process
(2014-01-01)
Techitdheera, Wicharn
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Rattanarak, Jiravat
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Mekprasart, Wanichaya
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Pecharapa, Wisanu
N-doped TiO<inf>2</inf> were prepared via ball milling process with different operating times and annealing temperatures. Commercial TiO<inf>2</inf> anatase powders used as TiO<inf>2</inf> precursor were dispersed in ammonia solution for nitrogen source. Ball milled TiO<inf>2</inf> powders at various times were annealed in nitrogen atmosphere at different temperatures. Physical properties and surface morphologies after ball milling process were monitored by X-ray diffraction (XRD) and scanning electron microscope (SEM). The component of samples was characterized by energy-dispersive X-ray spectroscopy (EDX). The active surface area of the samples was investigated by Brunauer Emmet Teller method. SEM result indicated that large particle of TiO<inf>2</inf> precursor could be reduced via ball milling process leading to high active surface area by the increase of milling time. XRD result showed the crystalline structures of TiO<inf>2</inf> after milling process and nitrogen annealing were identical to TiO<inf>2</inf> precursor structure. Meanwhile, the appearance of impurity phase in TiO<inf>2</inf> precursor was also depreciated via ball milling process with ammonia solution and annealing under nitrogen atmosphere.
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Microwave-assisted solution combustion synthesis and characterization of thermoelectric Ca3Co2O6 powders
(2013-10-29)
Kahatta, Sagulthai
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Chaiyo, Nopsiri
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Ruttanapun, Chesta
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Techitdheera, Wicharn
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Pecharapa, Wisanu
The microwave-assisted solution combustion synthesis was applied to the initial synthesizing of Ca<inf>3</inf>Co<inf>2</inf>O<inf>6</inf> powder using glycine as a fuel and nitrate as an oxidant. The assynthesized powders were calcined at 700-1,000°C for 4h. Product characterization was performed using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and Scanning electron microscope (SEM). The fuel-to-oxidizer molar ratio was found to affect the combustion reaction and character of the powder obtained. The phase composition of powder after calcination at various temperatures has shown that the formation of Ca<inf>3</inf>Co<inf>2</inf>O<inf>6</inf> occurs directly. The calcined powder possesses a rhombohedral crystal structure with an X-ray diffraction pattern that could be matched with the Ca<inf>3</inf>Co<inf>2</inf>O<inf>6</inf>JCPDS: 89-0629. This method is a simple way of synthesizing fine Ca<inf>3</inf>Co<inf>2</inf>O<inf>6</inf> powder with a low calcination temperature. © (2013) Trans Tech Publications, Switzerland.
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Modification of working electrode of dye-sensitized solar cell using TiO2 nanopraticles/TiO2 nanofibers/CNT composite
(2013-10-29)
Mekprasart, Wanichaya
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Jarernboon, Wirat
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Techitdheera, Wicharn
The working electrode of dye-sensitized solar cell was modified using composite material of TiO<inf>2</inf> particles/TiO<inf>2</inf> nanofibers/CNT by doctor blade method. Structural properties of pre-cursor materials and as-prepared working electrodes were well characterized by X-ray diffraction and scanning electron microscopy. The efficiency and relevant parameters of solar cells with modified electrodes were measured. The optimized weight ratios of 1 wt.% TiO<inf>2</inf> nanofibers derived from leucoxene and 0.01 wt.% CNT exhibited the highest improvement of DSSC efficiency with solar efficiency of 1.11% and fill factor of 0.32. The increase of current density may be originated from easier electron transfer that occurred in the device with modified TiO<inf>2</inf> particles/TiO<inf>2</inf> nanofibers/CNT composite. © (2013) Trans Tech Publications, Switzerland.
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Preparation and characterization of cu-doped ZnO sol-gel derived optical thin films
(2013-10-29)
Chongsri, Krisana
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Aunpang, Siriwattana
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Techitdheera, Wicharn
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Pecharapa, Wisanu
In this work, we report the preparation of Cu-doped ZnO thin films by sol-gel method based on zinc acetate dihydrate (CH<inf>3</inf>COO)<inf>2</inf>Zn·2H<inf>2</inf>O, Copper acetate dihydrate Cu<inf>3</inf>(CH<inf>3</inf>COO)<inf>2</inf>·H<inf>2</inf>O) and diethanolamine (HN(CH<inf>2</inf>OH)<inf>2</inf>, DEA). The precursor solution was prepared at various Cu composition ranging from 2-20 wt%. All films were spin-coated on borosilicate substrates for several coating repetition followed by annealing process at 550 °C for 4 h in an ambient air. The structural properties of the films were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The XRD results indicate the domination of hexagonal wurtzite structure of ZnO with noticeable alternation in the XRD peak intensity upon Cu doping content. SEM results revealed the grain size shape and surface morphologies of as-prepared samples. Crucial optical properties of as-prepared films were scrutinized from their UV-Vis transmission spectra. The films are highly transparent in the visible region with more than 90% transparency within 380 nm to 800 nm. Their corresponding band gaps indicate significant red shift with increasing Cu doping content. Overall results suggest that Cu additive play a vital role on relevant optical properties of ZnO that can be adjusted to meet the requirement for practical optoelectronics applications. © (2013) Trans Tech Publications, Switzerland.
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Photocatalytic activities under UV light of ball-milled TiO2photocatalysts
(2013-10-29)
Rattanarak, Jiravat
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Mekprasart, Wanichaya
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Pecharapa, Wisanu
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Techitdheera, Wicharn
Anatase TiO<inf>2</inf> powders used as photocatalysts were prepared by ball milling process at various milling time and annealed in nitrogen atmosphereat different temperatures. Commercial TiO<inf>2</inf> powders were ball-milled with ethanol at room temperature. After ball milling process, the samples were annealed in nitrogen atmosphere. The particle sizes and surface area of milled powders were measured by particle analyzer and Brunauer Emmet Teller method(BET). Effect of milling time and annealing temperature on structural properties of TiO<inf>2</inf> powders was investigated by X-ray diffraction(XRD) and scanning electron microscope(SEM). The degradation of aquous RhB dye by ball-milled TiO<inf>2</inf> powder photocatalyst was investigated under UV light irradiation. Comparing to P-25, TiO<inf>2</inf> powder prepared via ball milling process at 24 hr demonstrated significant enhancement in its photocatalytic activity under UV light due to the increasing active surface area after ball milling process. © (2013) Trans Tech Publications, Switzerland.
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Effect of Al and N doping on structural and optical properties of sol-gel derived ZnO thin films
(2013-02-01)
Bangbai, Chatpong
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Chongsri, Krisana
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Pecharapa, Wisanu
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Techitdheera, Wicharn
In this work, the preparation of ZnO, N-doped ZnO (NZO), Al-doped ZnO (AZO) and Al, N-doped ZnO (ANZO) thin films by the sol-gel spin-coating method is reported. The structural properties and surface morphologies of films were characterized by X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM). The optical properties of the films were interpreted from their transmission spectra using UV-VIS spectrophotometer. The XRD and SEM results disclosed that the crystallization quality and grain size of as-prepared films were highly influenced by N and Al doping. UV-VIS spectrophotometer results indicated that Al and N additives could significantly enhance the optical transparency and induce the blue-shift in optical bandgap of ZnO films.
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Influence of Ti and Zn dopants on structural properties and electrochromic performance of Sol-Gel derived WO3 thin films
(2013-01-01)
Paipitak, Kanokkorn
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Techitdheera, Wicharn
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Porntheeraphat, Supanit
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Pecharapa, Wisanu
The influence of different transition metals doping (Ti and Zn) on structural properties and electrochromic adjustment and performance of sol-gel derived WO<inf>3</inf> thin films was conducted and investigated. Ti-doped WO<inf>3</inf> and Zn-doped WO<inf>3</inf> thin films were deposited onto F-doped tin oxide (FTO) substrates using spin coating technique. Tungsten powder, Titanium butoxide and zinc acetate dehydrate were used as starting precursors. The as-deposited films were annealed at 500 °C for 2 h. The effect of Ti and Zn doping on structural, surface morphologies, optical properties of the films were examined using X-ray diffractometer, scanning electron microscope and UV-VIS spectrophotometer. The XRD analyses suggest that the crystalline of WO<inf>3</inf> can be identified as a monoclinic WO <inf>3</inf> structure. XRD results additionally indicate the existence of ZnWO<inf>4</inf> structure in the Zn-doped films, which is clearly observed by SEM. The optical measurement of all films indicate good transparency in the visible region and near infrared region with more than 60% in transmittance. 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 caused by close ionic radius of Ti to W rather than that of Zn. © 2013 The Authors.

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