The CaMgSi2O6:Eu2+, Mn2+ phosphors show three emission bands peaking at around 450nm (blue), 580nm (yellow), and 680nm (red). The blue band originates from the allowed f-d transition of Eu2+ ions on Ca sites. The yellow and red bands originate from the forbidden T14-A16 transition of Mn2+ ions on Mg2+ and Ca2+ sites, respectively. Electron paramagnetic resonance measurement demonstrates that Mn2+ ions occupy two different Ca2+ and Mg2+ sites. The mixtures of the green-poor CaMgSi2O6:Eu2+, Mn2+ and the green-to-yellow emissive (Ba,Sr)2SiO4:Eu2+, excited by the near ultraviolet of 365nm, show the various chromaticity of white light depending on the mixture ratio; the correlated color temperatures from 4845to9180K, and the color rendering indices from 71% to 88%.
Manganese-doped ZnS nanophosphors were synthesized by two different methods:
hydrothermal and low-temperature precipitation methods. The nanophosphors prepared by the
hydrothermal precipitation and low-temperature methods had the size of 20 nm and 4 nm,
respectively, and both were the cubic phase. The emission intensity of the nanophosphor prepared
by the hydrothermal method was optimized at 10 mole % of Mn2+ concentration whereas that by
low-temperature precipitation method was optimized at 3 mole % of Mn2+. The precipitationprepared
nanophosphor, of size 4nm, showed a blueshift in the excitation spectrum and a redshift in
the emission spectrum compared to the hydrothermal-prepared 20 nm nanophosphor. These
phenomena can be explained in terms of the quantum confinement effect. The decay times
especially were lengthened with decreasing particle size. This can be explained in terms of the
variation in the transition probability induced from the quantum confinement effect.
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