Dae Hee Son

Preparation of nickel powders from nickel salt by ultrasonic chemical reduction method

Submicron nickel powders have been synthesized successfully from aqueous NiCl 2 at various temperatures and times with ethanol-water solvent by using the conventional and ultrasonic chemical reduction method. The reductive condition was prepared by the dissolution of hydrazine hydrate into basic solution. The samples synthesized in various conditions were characterized by the means of an X-ray diffractometry (XRD), a scanning electron microscopy (SEM), a thermo-gravimetry (TG) and an X-ray photoelectron spectroscopy (XPS). It was found that the samples obtained by the ultrasonic method were more smoothly spherical in shape, smaller in size and narrower in particle size distribution, compared to the conventional one.

Microwave synthesis of oxovanadium phthalocyanine used as charge generation material

The feasibility of synthesizing oxovanadium phthalocyanine (VOPc) from vanadium oxide, dicyanobenzene, and ethylene glycol using the microwave synthesis was investigated by comparing reaction temperatures under the microwave irradiations with the same factors of conventional synthesis. The efficiency of microwave synthesis over the conventional synthesis was illustrated by the yield of crude VOPc. Polymorph of VOPc was obtained through the acid-treatment and recrystallization step. The VOPcs synthesized in various conditions were characterized by the means of an X-ray diffractometry (XRD), a scanning electron microscopy (SEM), and a transmission electron Microscopy (TEM).

Nanocrystalline Structure of Organic Photoconducting Materials Derived by Microwave Recrystallization Method

We investigated the feasibility of preparing nanocrystalline oxotitanium phthalocyanine (TiOPc) from crude TiOPc using liquid-phase direct recrystallization under the microwave irradiation. Different crystal structures and morphologies of TiOPc were obtained through acidtreatment and recrystallization method. The nanocrystalline TiOPcs prepared in various conditions were characterized by the means of an X-ray diffractometry (XRD), a transmission electron microscopy (TEM) and a photoconductivity measuring device.