Synthesis And Optical Properties Of Fluorescent Materials Doped With Divalent Ions

Fluorescent materials doped with divalent ions have attracted substantial attention owing to the broadness of their excitation and emission spectra, high intense band with chromatic peaks, and environmental friendliness. Photoluminescence properties of divalent ions can be significant effected by the crystal field due to their 5d shell, and the photoluminescence properties of the same divalent ion would be entirely different in different base materials. So, fluorescent materials doped with divalent ions are very promising and are therefore in the focus of current research activities.In this paper, the NaSr BO3: Ce2+/R(R= Dy2+、Ho3+、Er2+) phosphors, Ba4OCl6: Yb2+/Eu2+ phosphors and the YNbO4 phosphors were prepared by solid-state reaction, and the phase purity, photoluminescence and thermal quenching were investigated:Firstly, a series of NaSr BO3 co-doped with Ce2+/R(R= Dy2+、Ho3+、Er2+) were prepared by solid-state reaction. Under near-UV excitation at about 357 nm, NaSrBO3 doped with Ce2+ exist a blue emission with maximum at about 416 nm. However, after co-doped with Ce2+/R(R= Dy2+、Ho3+、Er2+), we found entirely different photoluminescence intensity among the phosphors. In NaSrBO3:Ce2+/ Dy2+, the optimal ions concentration was found to be 1% Ce2+and 1% Dy2+. In NaSrBO3:Ce2+/Er, the optimal ions concentration was found to be 0.5% Er and 1% Ce2+.Secondly, a series of Ba4OCl6: Yb2+ and Ba4OCl6: Yb2+/Eu2+ phosphors were prepared by solid-state reaction. Under near-UV excitation at about 330 nm, Ba4OCl6: Yb2+ and Ba4OCl6: Yb2+/Eu2+ exist similar blue emission with maximum at about 460 nm and FWHM about 75 nm, with a slightly red shift compared to Ba4OCl6:Eu2+. The broad asymmetric emission could be composed by two Gaussian bands emitted by the Yb2+ ions in two different Barium sites of Ba4OCl6. An energy transfer process with the impurity-trapped exciton state was supposed for the similarity of the photoluminescence properties.Thirdly, a series of LaMgAl10O17 ErxMny and Y0.958Al0.95Mg0.05O2.975Er0.01 Mnx phosphors were prepared by solid-state reaction. Under 980 nm laser excitation, the up-conversion photoluminescence properties of LaMgAl10O17 ErxMny and Y0.958Al0.95Mg0.05O2.975Er0.01 Mnx were investigated. The up-conversion emission peaks could be observed at approximately 524, 545, 665 and 850 nm. An energy transfer process was supposed for the quenching of the emission.