Flux-Assisted Preparation and Photoluminescence of Emission-Tunable (Sr,Eu)Al₂Si₂O8 Phosphors.

Abstract

We synthesized a emission tunable Eu(II)-activated SrAl2Si2O8 phosphors Eu(II)-activated SrAl2Si2O8 phosphors. The emission color could be controlled from blue to greenish-blue emissions via changing Sr/Eu ratio. The SrAl2Si2O8 and EuAl2Si2O8 phases were found to form a complete solid solution with composition of (Sr1-xEux)Al2Si2O8 (0 ≤ x ≤ 1.0), as indicated by X-ray diffraction analysis. Our research results also reveal that the use of fluxing agents of H3BO3 or LiBO2 in the materials synthesis plays a crucial role in improving the photoluminescence (PL) properties of (Sr,Eu)Al2Si2O8 phosphor and the surface morphology. The SrAl2Si2O8:Eu phosphors with varied Eu2+ contents show typical broad band emission in the range of 409 to 492 nm under ultraviolet excitation ranging from 352 to 380 nm. As indicated by the PL spectra of (Sr1-xEux)Al2Si2O8, the emission wavelength was found to red-shift, whereas the PL intensity was found to decrease with increasing doped Eu2+ content. Wide-range Commission Internationale de I'Eclairage (CIE) chromaticity coordinates from (0.15, 0.06) (when x = 0) to (0.23, 0.30) (when x = 1.0) can be achieved by properly adjusting the doped Eu2+ content in (Sr1-xEux)Al2Si2O8 phases. The optimization of preparation, correlation between crystal structure and luminescence properties, and microstructure of Eu2+-activated SrAl2Si2O8 are presented.