| Taking new borophosphate fluorescent materials as research objects, we recentlyfocused on rare earth compounds systems K2O-RE2O3-B2O3-P2O5(RE=Lu, Y), inorder to synthesize new borophosphates with unknown structures, which can beapplied in the field of luminescence. We synthesized two borophosphate compounds-K6Ln3B2P7O28(Ln=Lu, Y), analyzed their new crystal structures and studied theirpotential applications in luminescent materials. At the same time, we researched thephotoluminescence of KSr1-xBP2O8: x RE (RE=Eu2+, Tb3+, Eu3+) and KBa1-xBP2O8:x Eu2+. In the following, we list the main work in this paper:(1) We synthesized two new compounds-K6Ln3B2P7O28(Ln=Lu, Y) by boric acidflux method. Through structure analyse, we found the connection between BO4andPO4in the structure, which haven′t seen in the rare-earth borophosphates before. Thetwo compounds have similar crystal structures and both of them are belong to thecubic crystal system.[B2P7O28]15-are the FBU and aren′t connected with each other.F-ions don′t exit inside the structure as minerals.(2) K6Lu3-xB2P7O28: x RE (RE=Ce3+, Tb3+, Eu3+, Dy3+, Mn2+)and K6Y3-xB2P7O28: xRE (RE=Ce3+, Tb3+, Eu3+, Dy3+, Sm2+) were synthesized firstly by boric acid lowtemperature flux method. XRD patterns revealed that the doped ions didn′t changethe matrix single phase after doping rare earth ions. The luminescent analysisshowed that K6Ln2.97B2P7O28(Ln=Lu, Y):3%Ce3+present fast monoexponentialdecay. In K6Lu3-xB2P7O28: x Ce3+X-ray emission spectra, we can see the red-shift ofK6Lu3-xB2P7O28: x Ce3+emission peak. All the peaks are influenced by the lowest5dlevel to the2F5/2(4f1) and2F7/2(4f1) ground state. There are no great changes for theemission spectra of K6Ln2.97B2P7O28(Ln=Lu, Y):3%Tb3+under the NUV excitation.Tb3+doped phosphors emit bright green light in CIE color coordinate. AboutK6Ln2.97B2P7O28(Ln=Lu, Y):3%Eu3+phosphors, no remarkable difference was found with regard to the location of the Eu3+emission lines. Eu3+emits red light inCIE color coordinate. Compared with K6Lu3-xB2P7O28: x Dy3+, K6Y3-xB2P7O28: xDy3+phosphors emit bluer light, which may be caused by the different crystal fieldenvironment of Dy3+. Fluorescence intensity decreases as Dy2O3concentration loweror increases to over0.5%. The orange emission broad peak at the range of500-650nm in K6Lu3-xB2P7O28: x Mn2+is assigned to a transition from upper4T1gtothe ground6A1gstate of Mn2+ions. The best doping concentration is10%.K6Y3-xB2P7O28: x Sm3+phosphors emit red light under the excitation of NUV light,All the peaks are influenced by4G5/2â†'6HJ(J=5/2,7/2,9/2) transition of Sm3+ions.(3) Through high-temperature solid-state method, we prepared a series ofKSr1-xBP2O8: x RE (RE=Eu2+, Tb3+, Eu3+) and KBa1-xBP2O8: x Eu2+phosphors. Theproperties of these phosphors were characterized by XRD and fluorescencespectrophotometer (PL).After doping rare-earth ions, the analyses revealed that KMBP2O8(M=Sr, Ba)single phase was maintained in the phosphors by XRD patterns. The PL resultsshowed that KM1-xBP2O8: x Eu2+could emit the blue light with the broad band,which peaks are at about450nm. The emission hue of KM1-xBP2O8:x Eu2+can bechanged from blue to blue-white with the increase of doped Eu2+. In addition,KSr1-xBP2O8: x Tb3+and KSr1-xBP2O8: x Eu3+could emit green light and red lightunder excited by near-UV light with the optimal concentration values of4%Tb3+and8%Eu3+, respectively. Pumped by a380nm InGaN NUV chip, a warm whitelight LED with CIE (0.323,0.319) was fabricated using KBa0.97BP2O8:3%Eu2+and CaAlSiN3: Eu2+phosphors. The results show that KBa1-xBP2O8: x Eu2+phosphors have potential application in WLED. |
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