Luminescence, cathodoluminescence and Ce3+ → Eu2+ energy transfer and emission enhancement in the Sr5(PO4)3Cl:Ce3+,Eu2+ phosphor

Abstract

Ultraviolet and vacuum ultraviolet spectra are reported for Ce 3+ and Eu 2+ singly doped into the Sr 5 (PO 4 ) 3 Cl lattice, synthesized by a solid-state process. The maxima of the emission intensities are at 346 nm (Ce 3+ ) and 442 nm (Eu 2+ ), with lifetimes of 25 ns and 494 ns, respectively. The Ce 3+ excitation spectra exhibit five bands assigned to vibronic structures of the 4f 1 / 5d 1 electronic transition, in addition to the host absorption at 166 nm at 295 K. The 5d centroid shift is similar to that in SrCl 2 :Ce 3+ . The Eu 2+ excitation spectrum is mainly comprised of two 4f 7 / 4f 6 5d broad bands between 200 nm and 450 nm, peaking at 343 nm and 275 nm.Both of the singly doped systems exhibit concentration quenching, with energy transfer rates being in the low (ms) À1 range for concentrations up to 4 at.% of total cations. The energy transfer rates are linearly and quadratically related to dopant ion concentrations of Ce 3+ and Eu 2+ , respectively. The energy transfer between Ce 3+ and Eu 2+ in the co-doped Sr 5 (PO 4 ) 3 Cl lattice has been studied by the analysis of intensity and decay measurements of both Ce 3+ and Eu 2+ emissions. The electric dipole-electric dipole transfer has an efficiency of 91% in Sr 4.8Àx Ce 0.01 Eu x Na 0.01 (PO 4 ) 3 Cl, with a critical distance of 21 Å. Although energy transfer between Ce 3+ and Eu 2+ upon excitation into the overlapping Ce 3+ /Eu 2+ absorption band is definitely demonstrated by the dramatic shortening of Ce 3+ lifetime, the emission of Eu 2+ is also enhanced at low Ce 3+ concentrations using exclusive excitation into the Eu 2+ absorption band. The quantum yields (QY) of the co-doped system approach those of BaMgAl 10 O 17 :Eu 2+ (BAM) for the excitation wavelengths of 317 and 365 nm, but are inferior for 254 nm excitation. The addition of 1 at.% Ce 3+ to Sr 4.98 Eu 0.02 (PO 4 ) 3 Cl increases the QY by $20% of the original value. The cathodoluminesce of the co-doped phosphor is comparable to that of BAM, with CIE coordinates of the emission (0.274, 0.237), so that the application as a field emission display phosphor is proposed.

Ca3Lu(AlO)3(BO3)4 : Sm3+: a novel red-emitting phosphor with high colour purity for NUV-based warm white LEDs

“…Compared with some reported Sm 3+ activated phosphors, such as Y 2 WO 6 : Sm 3+ , Sr 3 La(VO 4 ) 3 : Sm 3+ , Ba 3 La(PO 4 ) 3 -: Tb 3+ ,Sm 3+ , CaSrSiO 4 : Ce 3+ ,Sm 3+ etc 15,[37][38][39] , the thermal stability of the as-synthesized phosphor seems to be much better. To further certify the relationship of luminescence with temperature and to determine the activation energy for thermal quenching, temperature-dependent PL spectra of CLAB : 0.05Sm 3+ were tted by using Arrhenius formula, 40,41…”

Effect of codoping Ce3+ on the luminescence properties of Sr9Mg1.5(PO4)7:Eu2+ orange–yellow phosphor

“…The luminescence of phosphors can be advanced effectively via the energy transfer (ET) from the sensitizer to the activator in some select lattices . Actually, there have been numerous reports about Eu 2+ ‐activated phosphors in which the luminescence property can be enhanced by codoping with Ce 3+ ions . It is reasonable to deduce that the Ce 3+ ion may be a promising sensitizer for Eu 2+ emission in the Sr 9 Mg 1.5 (PO 4 ) 7 host and the photoluminescence performance of Sr 9 Mg 1.5 (PO 4 ) 7 :Eu 2+ could be improved via realizing the sensitization effect between Ce 3+ and Eu 2+ ions.…”

Tunable emission color of Li2SrSiO4:Tb3+ due to cross‐relaxation process and optical thermometry investigation

“…Therefore, Tb 3+ activated phosphors with various emission colors can be attained by choosing a suitable matrix and appropriate concentration of Tb 3+ . The tuning-emitting color due to cross relaxation is special to Tb 3+ ions, whereas in other case of tunable emission color of RE 3+ , it is usually caused by energy transfer among lanthanide ions, 11,12 or from the host to RE activators. 13,14 Silicate compounds have been extensively studied as host material for phosphors when doped by lanthanide ions.…”