Preparation And Photoluminescence Of Two Kinds Oxide Phosphors Used In UV/N-UV LEDs

In Sr3B2SiO8, KSrBP2O8 and SrAl2Si2O8, the existence of tetrahedrons including [SiO4]4-, [PO4]4-/[PO3]2- and [AlO4]4- makes the compounds containing them are of a high chemical stability, which as luminescent hosting materials deserve systematical investigations. At the meanwhile, the rare earth (RE) has abundant energy levels structures and excitation modes, which therefore is supposed to be suitable for luminescent centers. Taking Sr3B2SiO8,KSrBP2O8 and SrAl2Si2O8 as research objects, we studied their luminescence properties in the ultraviolet(UV) region in this paper.Sr3B2SiO8:RE3+(RE=Eu3+, Dy3+, Ce3+, Tb3+), KSrBP2O8:RE(RE=Eu2+, Eu3+, Dy3+, Ce3+, Tb3+) and SrAl2Si2O8:Eu2+are firstly synthesized with high temperature solid-state reaction. Through investigating the UV luminescence properties of the three kinds of compounds, we revealed the luminescence phenomenon of various rare earths doped in Sr3B2SiOs and KSrBP2O8, as well as the self-reduction phenomenon of SrAl2Si2O8:Eu2+.The results can be illustrated as follow:(1) Through measuring and analyzing the UV excitation and emission spectra of Sr3B2SiO8:RE3+(RE=Eu3+, Dy3+, Ce3+, Tb3+), it is found that Sr3B2SiO8:0.045Eu3+has a strong absorption and displays a well red emission (NTSC:x=0.65, y=0.35) at an excitation wavelength of 393nm; The emission spectra of Sr3B2SiO8:0.02Dy3+is a multi-peak wide spectra whose dominant peak locating at 485 nm,575 nm and 666 nm. The excitation spectra observed at 575 nm displays a serial absorption peaks within 290-473 nm implying that Sr3B2SiO8:Dy3+can be excited by not only the UV or NUV but also blue ray, which both response a strong yellow emission; It is possible to realize white emission for Sr3B2SiO8:Sr3B2SiO8:xCe3+, yTb3+(0≤r≤0.004, 0≤k≤0.06) under an excitation of 352 nm through adapting the doping amount of the two RE and therefore adjusting the emission intensity.(2) Through measuring and analyzing the UV excitation and emission spectra of KSrBP2O8:RE(RE=Eu2+, Eu3+, Dy3+, Ce3+, Tb3+), it is found that KSrBP2O8:Eu2+ has a well blue emission at an excitation wavelength of 350nm. KSrBP2O8:Eu3+can be effective excited within the NUV region (393nm), its emission spectra is red light whose dominant peak lies at 611nm; The emission spectra of KSrBP2O8:Dy3+is a multi-peak wide spectra whose dominant peak locating at 485 nm,575 nm and 666 nm, and the excitation spectra observed at 575 nm displays a serial absorption peaks within 290-473nm; When excited at 303nm, the emission spectra of KSrBP2O8:Ce3+has a dominant peak of 368nm which belongs to UV emission; When excited at 250nm, KSrBP2O8:Tb3+has a dominant peak of 542nm which belongs to UV emission.(3) Measurements and analysis on the excitation and emission spectra of SrAl2Si2O8:Eu2+synthesized by different raw materials under various environments revealed that SrAl2Si2O8 can reduce the Eu3+into Eu2+automatically in air conditions.All above host materials doped with rare earth can be effectively excited with the UV-NUV regions which agree with the emission wavelength of LED chips. Therefore they can be considered as potential UV-NUV LED phosphors...