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: An efficient Near-Infrared (NIR) quantum cutting (QC) in Eu2+–Yb3+ co-doped Sr3Gd(PO4)3 phosphor has been investigated. Upon excitation of Eu2+ with an ultraviolent (UV) photon at 343nm, two NIR emissions have been obtained from 2F7/2 → 2F5/2 transition of Yb3+. The luminescence spectra both in visible (VIS) and NIR regions and decay lifetime curves of Eu2+ have been measured to prove energy transfer (ET) from Eu2+ to Yb3+. The highest energy transfer efficiency (ETE) related to Yb3+ concentration was found to be 85.3%. So that the Sr3Gd(PO4)3 co-doped with Eu2+ and Yb3+ may be candidates to modify the spectral and improve the solar cell efficiency. [Copyright &y& Elsevier]

Highlights: [•] Tri-doped Sr3AlO4F phosphors with Ce3+, Tb3+ and Yb3+ were synthesized. [•] The luminescence spectra and decay lifetime curves have been measured. [•] Energy transfer processes from Ce3+ →Tb3+ →Yb3+ were observed. [•] The energy transfer efficiency was also calculated. [•] The energy transfer mechanism was also discussed. [ABSTRACT FROM AUTHOR]

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: 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]