SrA1204：Eu2＋,Dy3＋ hollow microspheres were successfully prepared through a facile and mild solvothermal co-precipitation combining with a postcalcining process. The structure and particle morphology were investigated by X-ray diffxaction （XRD）, scanning and transmission electron microscopy （SEM and TEM） pictures, respectively. The mechanism for the formation of spherical SrAI204：Eu2＋,Dy3. phosphor was preliminary presented. After being irradiated with ultraviolet （UV） light, the spherical phosphor emitted long-lasting green phosphorescence. Both the photoluminescence （PL） spectra and luminance decay, compared with that of commercial bulky powders, revealed that the phosphors had efficient luminescent and long lasting properties. It was considered that the SrA1204：Eu2＋,Dy3. hollow microspheres had promising long-lasting phosphorescence with potential scale-dependent applications in photonic devices.
The yellow SrSi2O2N2：Eu2＋ phosphor has been synthesized by using a simple solid-state reaction method with Sr2SiO4：Eu2＋ as the precursor. It shows a broad excitation band extending from 250 to 520 nm and an asymmetric emission band with a main peak at about 550 nm. The emission intensity of the SrSi202N2：Eu2＋ is about 1.2 times higher than the commercial yellow phosphor YAG：Ce3＋ （P46-Y3）. The temperature- dependent luminescence characteristic of SrSi202N2：Eu2＋ has been investigated in this paper. With increasing temperature, the emission band of SrSi202N2：Eu2＋ shows anomalous blue-shift along with decreasing emission intensity and the broadening full width at half maximum （FWHM）. Particularly, compared with YAG：Ce3＋ （P46-Y3）, the yellow SrSi202N2：Eu2＋ phosphors exhibit higher thermal stability due to their weaker electron-phonon coupling strength （1.1）, lower stokes shift （0.0576 eV） and larger activation energy （0.288 eV）. All these results indicate that SrSi202N2：Eu2＋ yellow phosphors have potential application for white light-emitting diodes （LEDs）, What＇s more, an energy level scheme is constructed to explain the anomalous blue-shift phenomenon.
Jinlan QinChaofan HuBingfu LeiJinfang LiYingliang LiuShuiping YeMiaozhu Pan
