Search

Abstract: Ce3+ and Tb3+ co-doped BaAl2B2O7 phosphors were synthesized by the solid-state method. X-ray diffraction (XRD) was used to characterize the phase structure. The photoluminescent properties of Ce3+ and Tb3+ co-doped BaAl2B2O7 phosphors were investigated by using the photoluminescence emission and excitation spectra. Under the excitation of near ultraviolet (n-UV) light, BaAl2B2O7:Ce3+,Tb3+ phosphors exhibited blue emission corresponding to the f–d transition of Ce3+ ions and green emission bands corresponding to the f–f transition of Tb3+ ions, respectively. Effective energy transfer occurred from Ce3+ to Tb3+ in BaAl2B2O7 host due to the observed spectra overlap between the emission spectrum of Ce3+ ion and the excitation spectrum of Tb3+ ion. The energy transfer efficiency from Ce3+ ion to Tb3+ ion was also calculated to be 71%. Furthermore, the concentration quenching and critical distance of BaAl2B2O7:Ce3+,Tb3+ phosphors were also discussed. The energy transfer from Ce3+ to Tb3+ in BaAl2B2O7 host was demonstrated to be resonant type via a dipole–dipole interaction mechanism with the energy transfer critical distance of 16.13Å. [Copyright &y& Elsevier]

Abstract: Ce3+ and Tb3+ co-doped Sr3AlO4F phosphors were synthesized by the conventional high temperature solid-state method. X-ray diffraction (XRD) was used to characterize the phase structure. The luminescence spectra and decay lifetime curves of Ce3+ have been measured to prove energy transfer (ET) from Ce3+ to Tb3+. Under the excitation of near-ultraviolet light, Sr3AlO4F:Ce3+,Tb3+ phosphors exhibited blue emission corresponding to the f–d transition of Ce3+ ions and green emission bands corresponding to the f–f transition of Tb3+ ions, respectively. Effective energy transfer occurred from Ce3+ to Tb3+ in Sr3AlO4F host due to the observed spectra overlap between the emission spectrum of Ce3+ ion and the excitation spectrum of Tb3+ ion. The energy transfer efficiency from Ce3+ ion to Tb3+ ion was also calculated to be 51%. Furthermore, the energy transfer from Ce3+ to Tb3+ in Sr3AlO4F host was demonstrated to be resonant type via a dipole–dipole interaction mechanism. The present Ce3+ and Tb3+ co-doped Sr3AlO4F phosphor may have potential use in the technology of white light-emitting diodes. [Copyright &y& Elsevier]

Abstract: A series of new luminescent emission-tunable phosphors Sr3Gd(PO4)3(SGP):0.006Ce3+, xMn2+ have been synthesized by a high-temperature solid-state reaction. The energy transfer from Ce3+ to Mn2+ in SGP:Ce3+/Mn2+ phosphors has been validated and demonstrated to be a resonant type via a dipole–quadrupole mechanism based on the decay lifetime data, and the critical distance (R C ) calculated by quenching concentration method and spectral overlap method are 25.24 and 24.26Å, respectively. Tuning the Ce3+/Mn2+ ratio via the energy transfer varied the emission hue of from blue to white-light and eventually to yellow. These results indicate that the developed phosphor may be promising as a single-component white-light-emitting phosphor for white LEDs. [Copyright &y& Elsevier]

Abstract: Novel Ce3+- and Eu2+-coactivated Sr3Gd(PO4)3 phosphors were prepared by high temperature solid-state reactions. The Sr3Gd(PO4)3:Ce3+,Eu2+ phosphor showed two emission bands under 310nm excitation: the one observed at 374nm was assigned to the 4f 05d 1 →4f 1 transition of Ce3+ ion emission, and the other found at 518nm was attributed to the 4f 65d 1 →4f 7 transition of Eu2+ ions. The energy transfer from Ce3+ to Eu2+ in Sr3Gd(PO4)3 host matrix was studied and demonstrated to be a resonant type via a dipole–quadrupole mechanism. Furthermore, we have calculated the critical distance for Ce3+ →Eu2+ energy transfer to be about 32.02Å by the concentration-quenching method. Preliminary results indicate that the phosphor might be a promising green phosphor for UV-based white LEDs. [Copyright &y& Elsevier]