Keito Ohyama

Characteristics of up-conversion phosphor prepared by metal–organic decomposition method

Oxides can be formed from many materials by air sintering after coating a substrate with a metal–organic decomposition (MOD) solution. This enables the preparation of thin films by simple processes such as spin coating. The up-conversion (UC) phosphor produced by the MOD method has a multifunctional potential for use in applications such as displays and solid-state lighting. In this study, a simple TiO2–ZnO mixed oxide system was examined for use as the base material and host crystal of rare-earth (RE) elements for UC phosphor. The maximum emission luminescence of the UC phosphor was obtained when the mixing ratios of the base materials TiO2 : ZnO and additive materials Yb2O3 : Er2O3 were and , respectively. When the mixing ratio of the phosphor, Ti : Zn : Yb : Er, was , 550 nm green and 650 nm red emissions were produced. The UC emission intensity could be controlled by varying the mixing ratio of the rare-earth materials.

Strong light of red up-conversion in a ZnO-TiO 2 composite containing Er 3+ and Yb 3+

The up-conversion (UC) phosphor produced by a metal-organic decomposition (MOD) method has a multifunctional potential for use in applications such as displays and solid-state lighting. ZnO-TiO₂ composite system containing Er³⁺ and Yb³⁺ were prepared by solid state reaction method, and the composite phosphor shows bright red UC emission under 980 nm laser pumping. Two photon process was involved in the UC phenomenon of the Er, Yb:ZnO-TiO₂ phosphor. The effects of heating temperature, ZnO/TiO₂ composition and Er³⁺, Yb³⁺ concentrations on the UC emission behavior were examined. The ZnO-TiO₂ composite product sintered at 900 °C contained Zn₂TiO₄, TiO₂ and RE₂Ti₂O₇ (RE = Er³⁺ and Yb³⁺) phases and exhibited strong red emissions. The maximum emission luminescence of the UC phosphor was obtained when the mixing ratios of the base materials TiO₂ : ZnO and additive materials Yb₂O₃ : Er₂O₃ were 1 : 1 and 0:06 : 0:02, respectively. The ZnO-TiO₂:Er³⁺, Yb³⁺ phosphor was compared to the brightest available phosphor. It suggests that ZnO-TiO₂:Er³⁺, Yb³⁺ is a potential material for the red up-conversion phosphor.

Characteristics of up-conversion phosphor prepared using the MOD method

It is possible to form oxides of many materials by air sintering after coating the substrate with a metal-organic decomposition (MOD) solution, thus enabling the preparation of thin films by means of simple processes such as spin coating. MOD solutions of titanium oxide, zinc oxide, ytterbium oxide, and erbium oxide were used in this study. A mixture of Ti : Zn : Yb : Er was made by mixing the components at an arbitrary ratio, and after coating the substrate with the mixture, the sample was heated in air for 4 h at 1000 °C. The maximum value of the emission luminance of up-conversion (UC) phosphor was obtained when the mixing ratio of the base materials TiO2 : ZnO was 1 : 1. The emission intensity of UC could be controlled by varying the mixing ratio of rare earth content. UC phosphor produced by the MOD method has multifunctional potential such as for displays and solid-state lighting.

Bright yellow up-conversion in a LaOF containing Er 3+ and Yb 3+

LaF₃, metal-oxide system for use as the base material, containing Er³⁺ and Yb³⁺ for host crystal of rare-earth (RE) elements were prepared by solid state reaction method and its upconversion (UC) luminescence excited by 980 nm laser was studied. The effects of firing temperature, LaF3 with Er³⁺, Yb³⁺ concentrations on the UC emission behavior were examined. The LaOF product sintered at ffOO °C contained LaF₃ phases and exhibited strong green and red emissions arising due to the ²H_11/2, ⁴S_3/2→⁴Ii_5/2 and ⁴F_9/2→⁴Ii_5/2 transitions for Er³+ ion, respectively. Bright yellow color by the mixing of green and red colors was observed in the LaOF product doped with 0.01 at.% Er³⁺ and 0.01 at.% Yb³⁺. It suggests that LaOF : Er³⁺, Yb³⁺ is a potential material for the yellow upconversion phosphor.

Luminescence characterization of LaOF:Yb 3+ /Er 3+ up-conversion phosphor

Oxides can be formed from many materials by air sintering after coating a substrate with a metal-organic decomposition (MOD) solution. This enables the preparation of thin films by simple processes such as spin coating. The up-conversion (UC) phosphor produced by the MOD method has a multifunctional potential for use in applications such as displays and solid-state lighting. In this study, a simple LaF3 oxide system was examined for use as the base material and host crystal of rare-earth (RE) elements for UC phosphor. The maximum emission luminescence of the UC phosphor was obtained when the mixing ratios of the base materials LaF3 and additive materials Yb2O3:Er2O3 were 1:0.01:0.01, respectively. When the mixing ratio of the phosphor, LaF:Yb:Er, was 1:0.01:0.01, 550 nm green and 670 nm red emissions were produced. The UC emission intensity could be controlled by varying the mixing ratio of the rare-earth materials.