Study on the formation of solid solution when synthesizing manganese-doped zinc alkaline earth silicate luminescent pigment by impregnation - precipitation method

Abstract

This work refers to the research results on the ability to form solid solution when synthesizing the manganese-doped zinc alkaline earth silicate luminescent pigment in the form of Zn1,97-xMxMn0,03SiO4 (M is magnesium, calcium, strontium and barium) by the precipitation-impregnation method. The samples were characterized by thermal analysis, X-ray diffraction spectroscopy, luminescence under UV lamp and luminescence spectroscopy at 254 nm excitation wavelength. The results show that when heating the corresponding precipitated precursor at 900 oC for 45 minutes, in general, the ability to form solid solutions decreases when the size difference of alkaline earth metal ions with Zn2+ ions increases. Specifically, Mg2+ ions create single-phase solid solutions with x varying from 0 to 1. Ca2+ ions form solid solutions when x changes from 0 to 0.6. When x = 0.8; in addition to the main phase Zn2SiO4, it also creates Ca2ZnSi2O7 with tetragonal structure. The Ba2+ ions form solid solutions when x varies from 0 to 0.5. When x = 0.6, in addition to Zn2SiO4, there is also BaZn2Si2O7. The Sr2+ ions form a solid solution when x = 0.2. For samples with x ≥ 0.4, in addition to Zn2SiO4, there is also Sr2ZnSi2O7; SrZn2Si2O7/SrO.2ZnO.2SiO2. The single - phase solid solutions all have the rhombo H structure of Zn2SiO4, and all have higher luminescence than the multiphase samples. The sample with the largest x, the sample Zn0,97Mg1,0Mn0,03SiO4 had the highest luminescence, emitting green light corresponding to the wavelength of 525 nm when excited by 254 nm UV light.