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A series of Eu or Tb doped BaCa(BO) phosphors were synthesized by a high temperature solid state method, and the luminescence properties are investigated. BaCa(BO):Tb can show an obvious green emission, and the peak locates at 551 nm, which corresponds to the 5D→F transition of Tb. BaCa(BO):Eu can present the characteristic emission of Eu, and the peak locates at 600 nm, which is ascribed to the D→F transition of Eu. In order to achieve the emission-tunable phosphors, the Eu/Tb co-doped BaCa(BO) are synthesized. When tuning the Eu or Tb concentration, BaCa(BO):Eu, Tb can both show the tunable emission, which may be induced by the energy transfer from Tb to Eu. [ABSTRACT FROM AUTHOR]

Blue emitting phosphor SrZn(PO):Eu is synthesized by a high temperature solid state method, and the luminescent properties are investigated. At the 330 nm radiation excitation, SrZn(PO):Eu presents an emission band at 416 nm, which is assigned to the 4f5d→4f transition of Eu ion. The concentration quenching effect of Eu in SrZn(PO) has been validated and proved to be a resonant type via a dipole-dipole interaction. The critical distance ( R) of Eu in SrZn(PO) is calculated to be 3.244 nm. The Commission International de I'Eclairage (CIE) chromaticity coordinates of SrZn(PO):Eu locate at the blue region, such as (0.150, 0.072). The results indicate that the SrZn(PO):Eu phosphor may have potential applications in white light emitting diodes (LEDs). [ABSTRACT FROM AUTHOR]

For enhancing the emission intensity and broadening the excitation region of BaEu(PO) (BEP), Sm is doped as sensitizer in this paper. BEP:Sm can produce an obvious red emission at near ultraviolet (n-UV) radiation. An effective energy transfer from Sm to Eu3+ is proved. The commission international de I'Eclairage (CIE) chromaticity coordinates of BEP:Sm locate at red region. When the environment temperature is 150 °C, the emission intensity of BEP:0.10Sm is decreased to 76% of the initial one at room temperature, and the activation energy is calculated to be 0.164 eV, which can prove the good thermal stability of BEP:Sm. The results indicate that BEP:Sm may have potential applications in white light emitting diodes (LEDs). [ABSTRACT FROM AUTHOR]

SrZn(PO):Sm phosphor was synthesized by a high temperature solid-state reaction in atmosphere. SrZn(PO):Sm phosphor is efficiently excited by ultraviolet (UV) and blue light, and the emission peaks are assigned to the transitions of G-H (563 nm), G-H (597 nm and 605 nm) and G-H (644 nm and 653 nm). The emission intensities of SrZn(PO):Sm are influenced by Sm concentration, and the concentration quenching effect of SrZn(PO):Sm is also observed. When doping A ( A=Li, Na and K) ions, the emission intensity of SrZn(PO):Sm can be obviously enhanced. The Commission Internationale de l'Eclairage (CIE) color coordinates of SrZn(PO):Sm locate in the orange-red region. The results indicate that the phosphor has a potential application in white light emitting diodes (LEDs). [ABSTRACT FROM AUTHOR]

A white emitting phosphor of YAl(BO):Ce, Dy is synthesized by a solid state reaction, and its luminescent properties are investigated. Its phase formation is carried out with X-ray powder diffraction analysis, and there is no crystalline phase other than YAl(BO). YAl(BO):Ce can produce 422 nm blue emission under 367 nm excitation. The emission spectrum of YAl(BO):Dy shows several emission peaks under 350 nm excitation, and the peaks locate at 485 nm, 575 nm and 668 nm, respectively. Emission intensities of Ce and Dy in YAl(BO) are influenced by their concentrations, and the concentration quenching effect is observed. Energy transfer from Ce to Dy in YAl(BO) is validated and proved to be a resonant type via a quadrupole-quadrupole interaction, and the emission color can be tuned from blue to white by tuning the ratio of Ce/Dy. Moreover, the critical distance ( R) of Ce to Dy in YAl(BO) is calculated to be 1.904 nm. [ABSTRACT FROM AUTHOR]

A series of Ce, Eu and Ce-Eu doped CaAl(PO) phosphors are synthesized by a high temperature solid-state method. Under 291 nm excitation, CaAl(PO):Ce has one emission band at 356 nm, which is attributed to 4f5d→4f transition of Ce. Under 305 nm excitation, CaAl(PO):Eu presents one emission band at 445 nm, which is assigned to 4f5d→4f transition of Eu. Energy transfer from Ce to Eu in CaAl(PO) is validated and proved to be a resonant type via a quadrupole-quadrupole interaction. Critical distance ( R) of Ce to Eu in CaAl(PO) is calculated to be 1.264 nm. Moreover, the emission intensity of CaAl(PO):Ce, Eu can be tuned by properly adjusting the relative doping composition of Ce/Eu. [ABSTRACT FROM AUTHOR]

A series of Tb doped NaY(MoO) are synthesized by a solid-state reaction at 550 °C for 4 h, and their luminescent properties are investigated. The phase formation is carried out with X-ray powder diffraction analysis, and there is no other crystalline phase except NaY(MoO). NaY(MoO):Tb can produce the green emission under 290 nm radiation excitation, and the luminescence emission peak at 545 nm corresponds to the D→F transition of Tb. The emission intensity of Tb in NaY(MoO) is enhanced with the increase of Tb concentration, and there is no concentration quenching effect. The phenomena are proved by the decay curves of Tb. Moreover, the Commission International de I'Eclairage (CIE) chromaticity coordinates of NaY(MoO):Tb locate in the green region. [ABSTRACT FROM AUTHOR]

A series of SrY(PO):Eu samples are synthesized by the high temperature solid-state method. SrY(PO):Eu shows an asymmetrical emission band under excitation of 350 nm. The emission peaks at 426 nm and 497 nm are assigned to the nine-coordination Eu and six-coordination Eu, respectively. The effects of Eu doping content on the emission intensity and color are observed, and the concentration quenching effect is also observed. For two different Eu luminescence centers, the quenching mechanisms are dipole-dipole interaction and quadrupole-quadrupole interaction, respectively. And the critical distance of energy transfer is calculated by concentration quenching and turns out to be about 3.67 nm. The results above show that the asymmetrical emission band of SrY(PO):Eu comes from two different Eu luminescence centers in the lattice. [ABSTRACT FROM AUTHOR]

A series of Ce, Tb or Ce/Tb doped YAl(BO) phosphors are synthesized by a high temperature solid-state reaction, and their luminescent properties are investigated. YAl(BO):Ce shows a broad emission band at 422 nm under the 367 nm radiation excitation. YAl(BO):Tb can be efficiently excited by the ultraviolet (UV) light, and produces green emission. The emission intensity of YAl(BO):Tb can be enhanced by adjusting Tb doped content, and reaches the maximum at 0.06 mol Tb. When Ce is codoped, the emission intensity of Tb in YAl(BO) can be enhanced, but the commission international del'eclairage (CIE) chromaticity coordinates of YAl(BO):Tb have almost no change. Moreover, the energy transfer from Ce to Tb in YAl(BO) is studied. [ABSTRACT FROM AUTHOR]

A novel white-bluish emitting phosphor of (BaSr)BPO:0.02Eu is synthesized by the solid state reaction. (BaSr)BPO:0.02Eu can be effectively excited by 370 nm ultraviolet (UV) light, and exhibits two emission bands at 430 nm and 522 nm which are attributed to the d-f transitions of the Eu ions in two different cation sites in the host lattices. And the chromaticity coordinate of (BaSr)BPO:0.02Eu phosphor is (0.29, 0.25). [ABSTRACT FROM AUTHOR]