Formation of CuS with flower-like, hollow spherical, and tubular structures using the solvothermal-microwave process

Titipun Thongtem,Anukorn Phuruangrat,Somchai Thongtem 한국물리학회 2009 Current Applied Physics Vol.9 No.1

CuCl2 ․ 2H2O and CH3CSNH2 were dissolved in ethylene glycol, and followed by the addition of NaOH to form solutions with different pH values. Reactions proceeded in surfactant-free solutions contained in an acid digestion bomb using a microwave irradiation at different conditions. Pure CuS (hcp) with flower-like, hollow spherical, and tubular structures were detected, and had the same vibration wavenumber at 474 cm-1. They displayed two emission peaks at 411, and 432 nm. The formation of CuS with different morphologies was proposed according to the analytical results. CuCl2 ․ 2H2O and CH3CSNH2 were dissolved in ethylene glycol, and followed by the addition of NaOH to form solutions with different pH values. Reactions proceeded in surfactant-free solutions contained in an acid digestion bomb using a microwave irradiation at different conditions. Pure CuS (hcp) with flower-like, hollow spherical, and tubular structures were detected, and had the same vibration wavenumber at 474 cm-1. They displayed two emission peaks at 411, and 432 nm. The formation of CuS with different morphologies was proposed according to the analytical results.

Sonochemical synthesis of MMoO₄(M = Ca, Sr and Ba) nanocrystals

Titipun Thongtem,Anukorn Phuruangrat,Somchai Thongtem 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.2

MMoO₄ (M= Ca, Sr and Ba) were successfully produced using M(NO₃)₂·2H₂O and Na₂MoO₄·2H₂O in ethylene glycol by a 5 h sonochemical process. A tetragonal crystal system with a scheelite structure was detected using an X-ray diffractometer (XRD) and a selected area electron diffraction (SAED) technique. The calculated lattice parameters (a nm, c nm) are (0.5232, 1.1430), (0.5402, 1.2027) and (0.5560, 1.2766) for M = Ca, Sr and Ba, respectively. They are in accord with those of the corresponding JCPDS software. A transmission electron microscope (TEM) revealed the presence of nanocrystals in the products. Their sizes were 11.5 ± 3.1 nm, 15.9 ± 4.8 nm and 18.1 ± 4.8 nm for M = Ca, Sr and Ba, respectively. Their crystallographic planes were aligned in systematic arrays characterized using a high resolution transmission electron microscope (HRTEM). Six different vibration wavenumbers were detected using a Raman spectrometer and are specified as ν1(Ag), ν3(Bg), ν3(Eg), ν4(Bg), ν2(Ag) and νf.r.(Ag). A Fourier transform infrared (FTIR) spectrometer provided evidence of the scheelite structure with a Mo-O stretching vibration in MoO₄ ²− tetrahedrons at 740-950 cm−¹. MMoO₄ (M= Ca, Sr and Ba) were successfully produced using M(NO₃)₂·2H₂O and Na₂MoO₄·2H₂O in ethylene glycol by a 5 h sonochemical process. A tetragonal crystal system with a scheelite structure was detected using an X-ray diffractometer (XRD) and a selected area electron diffraction (SAED) technique. The calculated lattice parameters (a nm, c nm) are (0.5232, 1.1430), (0.5402, 1.2027) and (0.5560, 1.2766) for M = Ca, Sr and Ba, respectively. They are in accord with those of the corresponding JCPDS software. A transmission electron microscope (TEM) revealed the presence of nanocrystals in the products. Their sizes were 11.5 ± 3.1 nm, 15.9 ± 4.8 nm and 18.1 ± 4.8 nm for M = Ca, Sr and Ba, respectively. Their crystallographic planes were aligned in systematic arrays characterized using a high resolution transmission electron microscope (HRTEM). Six different vibration wavenumbers were detected using a Raman spectrometer and are specified as ν1(Ag), ν3(Bg), ν3(Eg), ν4(Bg), ν2(Ag) and νf.r.(Ag). A Fourier transform infrared (FTIR) spectrometer provided evidence of the scheelite structure with a Mo-O stretching vibration in MoO₄ ²− tetrahedrons at 740-950 cm−¹.

Preparation of flower-like PbS nano-structures using cyclic microwave radiation

Titipun Thongtem,Anukorn Phuruangrat,Somchai Thongtem 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.4

Flower-like PbS nano-structures were successfully prepared from different mole ratios of Pb(NO3)2 to CH5N3S in propylene glycol, using the cyclic process of 600 W microwave power for 15 minutes. PbS (cubic) was detected using X-ray diffraction (XRD) and selected area electron diffraction (SAED). The experimental and simulated patterns are in good accord. A Raman spectrometer revealed the presence of vibrations at 134, 275 and 431 cm−1. Flower-like PbS nano-structures were also characterized using a scanning electron microscope (SEM) and a transmission electron microscope (TEM), although the products were prepared using different mole ratios of the starting agents. Flower-like PbS nano-structures were successfully prepared from different mole ratios of Pb(NO3)2 to CH5N3S in propylene glycol, using the cyclic process of 600 W microwave power for 15 minutes. PbS (cubic) was detected using X-ray diffraction (XRD) and selected area electron diffraction (SAED). The experimental and simulated patterns are in good accord. A Raman spectrometer revealed the presence of vibrations at 134, 275 and 431 cm−1. Flower-like PbS nano-structures were also characterized using a scanning electron microscope (SEM) and a transmission electron microscope (TEM), although the products were prepared using different mole ratios of the starting agents.

Synthesis of CaWO₄, SrWO₄ and BaWO₄ with nanosized particles using cyclic microwave radiation

Titipun Thongtem,Anukorn Phuruangrat,Somchai Thongtem 한양대학교 세라믹연구소 2008 Journal of Ceramic Processing Research Vol.9 No.3

Scheelite tungstates (MWO4, M = Ca, Sr and Ba) were successfully synthesized by the reactions of M(NO3)2·2H2O and Na2WO4·2H2O in propylene glycol and NaOH using cyclic microwave radiation. The tungstates were detected using SAED. TEM and SEM analyses revealed the presence of dispersed nanosized particles for CaWO4, nanosized particles in irregular clusters for SrWO4, and nanosized particles in clusters shaped like dumb-bells for BaWO4. Raman spectra provide evidence of the scheelite structure with six different vibration modes. Arrays of crystallographic planes were detected using HRTEM. PL emission of the products is caused by the 1T2→ 1A1 transition of electrons within [WO4]2− tetrahedrons in the blue spectral region at 407-419 nm. Scheelite tungstates (MWO4, M = Ca, Sr and Ba) were successfully synthesized by the reactions of M(NO3)2·2H2O and Na2WO4·2H2O in propylene glycol and NaOH using cyclic microwave radiation. The tungstates were detected using SAED. TEM and SEM analyses revealed the presence of dispersed nanosized particles for CaWO4, nanosized particles in irregular clusters for SrWO4, and nanosized particles in clusters shaped like dumb-bells for BaWO4. Raman spectra provide evidence of the scheelite structure with six different vibration modes. Arrays of crystallographic planes were detected using HRTEM. PL emission of the products is caused by the 1T2→ 1A1 transition of electrons within [WO4]2− tetrahedrons in the blue spectral region at 407-419 nm.

Effect of basicity on the morphologies of ZnO produced using a sonochemical method

Titipun Thongtem,Anukorn Phuruangrat,Somchai Thongtem 한국물리학회 2009 Current Applied Physics Vol.9 No.3

Wurtzite ZnO was produced by the sonochemical reactions of 0.005 mol Zn(NO3)2 and different moles of NaOH in de-ionized water. The phase was characterized using X-ray diffraction (XRD) and selected area electron diffraction (SAED). A Raman peak was clearly detected at 435 cm-1. The SAED patterns were in accordance with those of the simulation. Scanning and transmission electron microscopies (SEM and TEM) revealed the presence of 72 ± 17 nm nano-particles, and nano-plates and spear-shaped particles in flower-like clusters, influenced by basicity conditions. By using high-resolution TEM (HRTEM), a spear was observed growing in the [001] direction normal to its (002) plane. Wurtzite ZnO was produced by the sonochemical reactions of 0.005 mol Zn(NO3)2 and different moles of NaOH in de-ionized water. The phase was characterized using X-ray diffraction (XRD) and selected area electron diffraction (SAED). A Raman peak was clearly detected at 435 cm-1. The SAED patterns were in accordance with those of the simulation. Scanning and transmission electron microscopies (SEM and TEM) revealed the presence of 72 ± 17 nm nano-particles, and nano-plates and spear-shaped particles in flower-like clusters, influenced by basicity conditions. By using high-resolution TEM (HRTEM), a spear was observed growing in the [001] direction normal to its (002) plane.

Solvothermal synthesis of CdS nanorods using hydroxyethyl cellulose as a template

Titipun Thongtem,Chalermchai Pilapong,Somchai Thongtem 한국물리학회 2009 Current Applied Physics Vol.9 No.6

CdS nanorods were solvothermally produced from Cd(CH3COO)2 and S powder using ethylenediamine (en) as a solvent and hydroxyethyl cellulose (HEC) as a template. The phase with hexagonal structure was detected using XRD and SAED, which is in perfect accordance with the results obtained by simulation. SEM, TEM and HRTEM revealed the development of nanorods with a number of atoms arranged in crystal lattices. When the appropriate amount of HEC was used, the longest nanorods, with preferential growth in the [001] direction, were produced. Raman spectra showed the fundamental and overtone modes at the same wavenumbers of 301 and 599 cm-1, respectively. Their relative intensities at each temperature were strongly influenced by the anisotropic geometry of the products. Photoluminescence caused by electronhole recombination was detected at 470 nm, and by surface trapping induced emission at 575 nm. The formation mechanism of CdS nanorods was also proposed based on the experimental results. CdS nanorods were solvothermally produced from Cd(CH3COO)2 and S powder using ethylenediamine (en) as a solvent and hydroxyethyl cellulose (HEC) as a template. The phase with hexagonal structure was detected using XRD and SAED, which is in perfect accordance with the results obtained by simulation. SEM, TEM and HRTEM revealed the development of nanorods with a number of atoms arranged in crystal lattices. When the appropriate amount of HEC was used, the longest nanorods, with preferential growth in the [001] direction, were produced. Raman spectra showed the fundamental and overtone modes at the same wavenumbers of 301 and 599 cm-1, respectively. Their relative intensities at each temperature were strongly influenced by the anisotropic geometry of the products. Photoluminescence caused by electronhole recombination was detected at 470 nm, and by surface trapping induced emission at 575 nm. The formation mechanism of CdS nanorods was also proposed based on the experimental results.

Hydroxyethyl cellulose-assisted hydrothermal synthesis of Bi2S3 urchin-like colonies

Titipun Thongtem,Siriprapha Jattukul,Chalermchai Pilapong,Somchai Thongtem 한국물리학회 2012 Current Applied Physics Vol.12 No.1

Orthorhombic Bi2S3 with different morphologies was successfully synthesized by the acid-catalyst hydrothermal reactions of bismuth nitrate (Bi(NO3)3) and thiourea (NH2CSNH2) solutions containing different amounts of hydroxyethyl cellulose (HEC). Phase, morphologies, and optical properties were characterized by X-ray diffraction, selected area electron diffraction, scanning and transmission electron microscopy, and ultravioletevisible spectroscopy. The products, hydrothermally synthesized in the HECfree,0.25 g HEC-added, 0.5 g HEC-added and 1.00 g HEC-added solutions, were respectively proved to be orthorhombic Bi2S3 irregular nanorods, complete urchin-like colonies of regular nanorods, incomplete urchin-like colonies of regular nanorods, and highly crystalline regular nanorods growing along the [001]direction. Tauc band gaps of the orthorhombic Bi2S3 nanorods, synthesized in the HEC-free, 0.25 g HECadded,and 1.00 g HEC-added solutions were determined to be 3.0, 1.75 and 1.8 eV, respectively. Formation mechanism of orthorhombic Bi2S3 nanorods, synthesized in the HEC-free and HEC-added solutions, was also discussed at great detail. Orthorhombic Bi2S3 with different morphologies was successfully synthesized by the acid-catalyst hydrothermal reactions of bismuth nitrate (Bi(NO3)3) and thiourea (NH2CSNH2) solutions containing different amounts of hydroxyethyl cellulose (HEC). Phase, morphologies, and optical properties were characterized by X-ray diffraction, selected area electron diffraction, scanning and transmission electron microscopy, and ultravioletevisible spectroscopy. The products, hydrothermally synthesized in the HECfree,0.25 g HEC-added, 0.5 g HEC-added and 1.00 g HEC-added solutions, were respectively proved to be orthorhombic Bi2S3 irregular nanorods, complete urchin-like colonies of regular nanorods, incomplete urchin-like colonies of regular nanorods, and highly crystalline regular nanorods growing along the [001]direction. Tauc band gaps of the orthorhombic Bi2S3 nanorods, synthesized in the HEC-free, 0.25 g HECadded,and 1.00 g HEC-added solutions were determined to be 3.0, 1.75 and 1.8 eV, respectively. Formation mechanism of orthorhombic Bi2S3 nanorods, synthesized in the HEC-free and HEC-added solutions, was also discussed at great detail.

Preparation and characterization of nanocrystalline SrWO₄ using cyclic microwave radiation

Titipun Thongtem,Anukorn Phuruangrat,Somchai Thongtem 한국물리학회 2008 Current Applied Physics Vol.8 No.2

Nanocrystalline SrWO₄ was successfully prepared using SrCl₂ and Na₂WO₄ in ethylene glycol at dierent pH values, microwave pow-the presence of nano-sized crystals with their crystallographic planes aligning in systematic order. Raman and FTIR spectra provide theevidence of scheelite structure with WO stretching vibration in WO₄²- tetrahedrons at 781-912 cm-¹. PL emission of the products isconsidered to be from the¹T₂ → ₁A¹ transition of electrons within [WO₄]²-. tetrahedrons at 420-428 nm (2.901-2.956 eV).

Preparation and characterization of rutile TiO₂films

Suparut Narksitipan,Somchai Thongtem 한양대학교 세라믹연구소 2012 Journal of Ceramic Processing Research Vol.13 No.1

Rutile titanium dioxide (TiO2) films were prepared by calcination for 4 h at temperatures in the range 550-700oC. Their structure and crystalline nature were investigated by X-ray diffraction (XRD), selected area electron diffraction (SAED) and Raman spectroscopy. After film preparation at 700oC, rutile TiO2 with a tetragonal structure was detected. Raman spectra displayed centered bands at 235, 440 and 603 cm−1, corresponding to the rutile structure of TiO2. The intensity of rutile TiO2increased with an increase in the calcination temperatures. The Raman spectra agree very well with SAED patterns. In addition, the characterization of rutile films with (scanning electron microscopy) SEM and atomic force microscopy (AFM)showed a surface roughness and dense particles with an angular shape.

Structure and optical properties of anatase thin films produced by filtered cathodic vacuum arc method

Sakon Sansongsiri,Somchai Thongtem 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.12

Titanium dioxide (TiO2) thin films were deposited on glass substrates by filtered cathodic vacuum arc system (lab-made) forvarious number of pulse modes at -50 VDC, and followed by 450 oC annealing in air for 1 hr. The deposition pulses were 500-2,000 pulses and the anatase film thickness was 13.0-37.5 nm. In this research, the roughness was increased with the increasingin the number of deposition pulses and film thickness. The transmission at 600 nm wavelength was 65-85%, decreasing withthe film thickness, and the optical energy gap was in the range of 3.55-3.65 eV