Russameeruk Noonuruk

Characterization and Phase Formation Study of ZnO:Sn Nanoparticles Synthesized by Co-precipitation Method

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.

Physical, Electrical and Optical Properties of F/Sb Codoped SnO2 Synthesized Via Sonochemical Process

F/Sb-codoped SnO2 nanoparticles were synthesized via sonochemical process using stannic chloride pentahydrate (SnCl4·5H2O) as host precursor while antimony(III) chloride (SbCl3) and ammonium fluoride (NH4F) were chosen as Sb and F dopant precursors, respectively. Their physical properties and morphologies were investigated using X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscope while their electrical and optical properties were investigated by Hall measurement and diffuse reflectance spectroscopy. As-synthesized powder of polycrystalline phase SnO2 nanoparticles can be obtained by one-step sonochemical process and its crystallinity can be improved by calcination process. The formation of crystalline phase of SnO2 is assisted by cavitation effect provided by intense ultrasonic radiation via rapid collision. The characterization results disclose that Sb dopant has strong influence on both physical and electrical properties while F dopant provide considerable effect on electrical property of the samples. It is noticed that the codoping of both elements with certain contents can significantly heighten its electrical conductivity.

SnO2 Nanoparticle Synthesized by Ultrasonic-Assisted Process

SnO2 nanoparticles were synthesized by ultrasonic-assisted precipitation process using stannic chloride pentahydrate (SnCl4·5H2O) as a precursor. The stannic chloride aqueous solution was precipitated by ammonia under sonication. The as-synthesized precipitates were dried at 80 oC and then calcined at 400 oC for 2 h. The physical properties of nanoparticles with/without sonication were characterized by thermogravimetic and differential thermal analysis, X-ray diffraction, and transmission electron microscope. The results reveal that ultrasonic radiation has significant influence on phase transformation mechanism from Sn (OH)4 to SnO2, grain size and uniformity of SnO2 nanoparticles.

Indium Tin Oxide conductive nanoparticles synthesized by sonochemical method

ABSTRACT This work reports the synthesis of Indium Tin Oxide (ITO) nanoparticles via sonochemical process at various calcination temperature using InCl3 and SnCl4·5H2O 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.

Influence of annealing temperature on optical properties of fluoride doped tin oxide films grown by the sol-gel spin-coating method

ABSTRACT Fluoride-doped Tin Oxide (FTO) thin films were deposited on glass and silicon substrates by the sol-gel spin-coating method using stannic chloride pentahydrate (SnCl4·5H2O) and ammonium fluoride (NH4F) as starting precursors for Sn and F sources. As-deposited films were annealed at different temperatures ranging from 300–600°C. The effect of annealing temperature on structural and optical properties of FTO thin films including crystallinity, surface morphology, optical transparency, optical reflectivity and optical band gap are investigated by X-ray diffraction, scanning electron microscopy and UV-VIS spectrophotometry. The XRD results suggest that the prominent peak in the (110) orientation can be indexed to the polycrystalline SnO2 structure without any impurity phase caused by fluoride doping. The transmittance spectra of fluoride-doped tin oxide thin films show good transparency in the visible region with noticeable variation in its structural and optical reflectance properties depending on annealing temperature.

Physical and Optical Properties of Indium Oxide: Tin Nanoparticles Synthesized by Co-Precipitation Method

Indium oxide:tin nanoparticles were synthesized by co-precipitation method using InCl3 and SnCl4·5H2O 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%) SnO2 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.

Effect of Sputtering Power on Physical Properties and Electrochromic Performance of Sputtered-WO3 Thin Films

Tungsten oxide (WO3) electrochromic thin films were deposited onto F-doped tin oxide (FTO) substrates using DC sputtering of tungsten target in presence of oxygen and argon gas. As-deposited films were prepared with different sputtering power at 50 W, 100W and 200W. The effect of power on structural, surface morphology optical and electrochromic properties of the WO3 thin films were characterized by X-ray diffractometer, scanning electron microscope, UV-VIS spectrophotometer and Cyclic voltammetry, respectively. The XRD results show that the crystalline of WO3 can be identified an orientation growth along (222) plane. The average grain size evaluated from SEM image is approximately 200 nm. The films deposited at power of 200 W exhibited better electrochromic properties with greatest optical modulation (∆T) value of ∆T = 31.2 % at l= 550 nm. The cyclic voltammograms (CV) of WO3 thin films evidently exhibited that the WO3 films prepared at power of 200 W displayed the superior electrochromic performance, compared to the others.