Preparation And Luminescence Properties Of Aluminate Phosphors

Rare-earth luminescent materials have attracted a lot of attention because of their application in LED lighting, information display, information transmission and so on. In this paper, ZnAl₂O₄: Eu³⁺, ZnAl₂O₄: Tb³⁺ and LaAlO₃: Eu³⁺ phosphors were obtained through the surfactant-assisted coprecipitation method. Structural and optical properties phosphors at different doping concentrations and annealed temperatures were mainly studied.1. ZnAl₂O₄: Eu³⁺ phosphors were synthesized through the CTAB-assisted coprecipitation method and characterized by XRD, SEM and photoluminescence （PL）. Products belong to clinic system and Z = 8. X-ray diffraction showed that the crystallization properties of ZnAl₂O₄: Eu³⁺ is perfect at low-doped concentration, yet the concentration is higher than 5%, the quality of crystallization decreases. Furthermore, higher temperature would enhance the crystallization properties of phosphors and could increase the particle size. When the annealed temperature is 700°C, a good crystallization has formed. The measurements reported that the lighting of ZnAl₂O₄: Eu³⁺ is mainly red, the dominant wavelength is 616 nm attributing to 5D0â†'7F2 transfer. When the annealed temperature is 800°C and doped concentration is 5%, ZnAl₂O₄: Eu³⁺ phosphor has the highest PL intensity and its chromaticity coordinate is x = 0.6513,y = 0.3415.2. ZnAl₂O₄: Tb³⁺ phosphors were prepared through the PEG200-assisted coprecipitation method and characterized by XRD, TG-DTA and photoluminescence. Products were ZnAl₂O₄: Tb³⁺ phosphors which belong to clinic system. When the annealed temperature is 700°C, a good crystallization has formed. When the concentration is higher than 5%, the quality of crystallization would decrease. PL analysis showed that the lighting of ZnAl₂O₄: Tb³⁺ is mainly green, the dominant wavelength is 544 nm attributing to 5D4â†'7F5 transfer of Tb³⁺. PL intensity of ZnAl₂O₄: Tb³⁺ reaches a maximum value at doped concentration around 5% annealed at 600°C.3. LaAlO₃: Eu³⁺phosphors were prepared through the CTAB-assisted coprecipitation method and characterized by XRD, SEM and PL. Products were LaAlO₃:Eu³⁺ phosphors which belong to rhombohedral system at 500°C⁸00°C. Higher temperature would enhance the crystallization properties of phosphors and could increase the particle size. When the temperature is 900°C, the impurity phase La10Al4O21 began to form. Doped concentration has little influence in the crystalline phase. The result showed that that the lighting of LaAlO₃:Eu³⁺ is mainly red, the dominant wavelength is 617 nm attributing to 5D0â†'7F2 transfer. PL intensity reaches a maximum value at doping concentration around 4% annealed at 800°C.