Ayano Toda

Improvement of luminescence properties of rubidium vanadate, RbVO3, phosphors by erbium doping in the crystal lattice

Greenish-white emitting Rb1−xErxVO3 (0 ≤ x ≤ 0.10) phosphors were synthesized by a conventional solid state reaction method. The thermal quenching effect of the RbVO3 phosphors was effectively improved by Er3+ doping into the RbVO3 lattice. Consequently, the emission peak intensity of the phosphors was successfully enhanced by Er3+ doping, and the internal quantum efficiency of Rb0.99Er0.01VO3 under excitation at 360 nm was 80%.

Novel Soft Chemical Synthesis Methods of Ceramic Materials

We report novel soft chemical synthesis method, solid hydratethermal reaction (SHR) method as a new soft chemistry. This method is very simple and can synthesize the ceramic materials just by storing the mixture of raw materials added a small amount of water in a reactor at low temperature below 373 K. For example, nanosize YVO4 (under 100 nm in diameter) was obtained using the SHR method.

Nanophosphors synthesized by the water-assisted solid-state reaction (WASSR) method: Luminescence properties and reaction mechanism of the WASSR method

ABSTRACT Ceramic materials have been widely used in various applications and are significantly important in our daily life. The various methods for synthesizing ceramics powder materials have been already reported, and the synthesis method is known to considerably affect the characteristics and particle morphology of ceramic powder materials. We have recently developed a novel soft chemical synthesis method, named water-assisted solid-state reaction (WASSR) method, which can be synthesized at low temperatures below 100°C. We further demonstrated the effect and availability of this method on the synthesis process for ceramic oxide materials. In this paper, we review some results for the nanophosphors synthesized by the WASSR method and discuss the reaction mechanism of this method.

Development of Water Assisted Solid State Reaction for the Ceramic Materials

We report a novel soft chemical synthesis method, water assisted solid state reaction (WASSR) method. This method is very simple and can synthesize many ceramic materials just by storing or mixing raw materials added a small amount of water in a reactor at low temperature below 373 K. For example, well-crystalline SrMoO4 was obtained using the WASSR method.

Morphology Control of Phosphors Synthesized by Microwave Heating Method

Ba2Gd3Li3Mo8O32:Eu3+ phosphor was prepared using a single mode microwave oven operated at a frequency of 2.45 GHz and a power of 500 W. The temperature of raw materials, mixtures of BaCO3, Gd2O3, Li2CO3, MoO3 and Eu2O3 subjected to microwave irradiation increased to about 1073 K in 120 s, followed by a sharp drop despite irradiating the raw materials continuously. By measuring the dielectric loss factor of the raw materials at 2.45 GHz, the temperature increased could be attributed to the fact that MoO3 absorbs a high proportion of microwave energy. In the case of the microwave heating method, the phosphor particles were highly non-aggregated.

Luminescence Properties of Y(P,V)O4 Synthesized by Microwave Heating

Eu3+ doped and undoped Y(P,V)O4 phosphors were prepared using multi-mode and single-mode microwave oven operated at 2.45 GHz. In the case of the microwave heating method, the phosphor particles were non-aggregated. A homogeneous distribution of Eu ion was observed in the microwave synthesis. No sintering behavior found in the microwave heating may be attributed to a quite shorter heating time. The Eu3+ doped sample synthesized by microwave heating showed intense red emission under UV excitation.