Papers by Author: Yi Kun Liao

Abstract: Ultrafine cerium-doped GSAG phosphor powders are prepared by a solution combustion process using glycine and urea as fuel. Single-phase cubic GSAG:Ce crystalline powder is obtained by calcining the as-synthesized amorphous materials at 800oC and no intermediate phase is observed. Transmission electronic microscope morphology shows that the resultant GSAG:Ce powders have uniform size and good homogeneity. The photoluminescence spectra of Ce3+ substituted for Ce3+ in GSAG has been measured on samples calcined at 1000oC.

Abstract: La2(MoO4)3 microcrystals with rodlike morphology have been successfully grown through hydrothermal microemulsion process at 180°C, pH =9 and 12 h. Quaternary microemulsion is composed of CTAB/water/hexane/n-pentanol. The obtained sample is characterized by means of XRD, FESEM, TEM. Formation mechanism is preliminarily discussed.

Abstract: Ultrafine terbium-doped Lu2Hf2O7/Tb phosphor powders are prepared by a solution combustion process using glycine and urea as fuel. Phase evolution of the synthesized powder is determined by X-ray diffraction (XRD) techniques. Single-phase cubic Lu2Hf2O7/Tb crystalline powder is obtained by calcining the amorphous materials at 800oC and no intermediate phase is observed. Transmission electronic microscope (TEM) morphology shows that the resultant Lu2Hf2O7/Tb powders have uniform size and good homogeneity. The photoluminescence (PL) spectra of Tb3+ substituted for Lu3+ in Lu2Hf2O7 with different content has been measured on samples calcined at 1000oC.

Abstract: Y2Hf2O7 and Lu2Hf2O7 precursor powders are prepared by nitrate solution combustion method with various fuels at 450°C, respectively. Phase evolution of the synthesized powders was determined by X-ray diffraction (XRD) techniques. Single-phase cubic Y2Hf2O7 and Lu2Hf2O7 crystalline powders were obtained by calcining the resultant combustion ash at 800°C for 2h. By controlling the pH of the nitrate solution, the type of fuel and the ratio of fuel/nitrate, nanosized powders can be obtained. The crystallite size of resultant powders is much related to the combustion flame temperature, which can be controlled by controlling the type of fuel and adjusting the fuel-to-oxidizer ratio. The influence of the ratio of reactants and the type of fuel on the properties of the final products was investigated. The crystal size and morphology were analyzed by TEM.