新型红色荧光粉Na2Ca4(PO4)2SiO4: Eu(上标 3+), Bi(上标 3+)的制备及发光特性

Novel red-emit phosphors, Na2Ca4(subscript (1-x-y))(PO4)2SiO4: xEu(superscript 3+), yBi(superscript 3+) were synthesized for WLED by conventional solid-state reaction at 1 200 ℃. Effects of the H3BO3 flux, the re-calcination time and doping concentrations of Eu(superscript 3+), Bi(superscript 3+) on the luminescence properties were investigated. It was found that a higher Eu(superscript 3+) emission intensity can be obtained if 30% H3BO3 was added as flux. No apparently structure transformation of the Na2Ca4(PO4)2SiO4 matrix was observed after doping Eu(superscript 3+), Bi(superscript 3+). The phosphors give the characteristic emission of Eu(superscript 3+) at 615 nm under the excitation of 395 nm. Samples re-calcined at 1 200 ℃ for 1.5 h gives a strongest emission. The red emission of Eu(superscript 3+) can be significantly enhanced by co-doping of Bi(superscript 3+) via an energy transfer process which involves the charge transfer (CT) transition of Eu(superscript 3+)-O(superscript 2-)→Bi(superscript 3+)→Eu(superscript 3+). The optimized doping mole fractions of Eu(superscript 3+) and Bi(superscript 3+) are x=0.04 and y=0.01, respectively. It shows that the Na2Ca4-(PO4)2SiO4: Eu(superscript 3+), Bi(superscript 3+) is a promising red phosphor for NUV-chips based WLED.