Low-temperature VUV photoluminescence and thermoluminescence of UV excited afterglow phosphor Sr₃Al_xSi_1−xO₅:Ce³⁺,Ln³⁺ (Ln = Er, Nd, Sm, Dy and Tm)

Abstract

Low-temperature (10 K) photoluminescence excitation and emission spectra of undoped Sr3SiO5 as well as Ce(3+) and Eu(3+) single doped Sr3SiO5 have been investigated. They show the host exciton band and the O(2-) to Eu(3+) charge transfer band at 5.98 eV (207 nm) and 3.87 eV (320 nm) respectively. Low-temperature thermoluminescence measurements are reported for Ce(3+) and lanthanide (Er, Nd, Sm, Dy, Er and Tm) co-doped Sr3AlxSi1-xO5. The results show that Ce(3+) is the recombination centre and Nd, Sm, Dy and Tm work as electron traps with trap depths of 0.95 eV, 1.89 eV, 1.02 eV, and 1.19 eV, respectively. Thermoluminescence excitation spectra of Sr2.98Al0.02Si0.98O5:0.01Ce(3+),0.01Dy(3+) show that the traps can be charged by 260 nm UV excitation.

Thermoluminescence as a Research Tool to Investigate Luminescence Mechanisms

“…If we replace Ce 3+ in this host material by Pr 3+ with lanthanides as codopants, the same results are obtained with Pr 3+ as the luminescent center [31]. A similar study on the energy level positions was performed on GdAlO 3 :Ce 3+ ,Ln (Ln = Pr, Er, Nd, Ho, Dy, Tm) (see Figure 7) and lanthanides in Y 3 Al 5 O 12 [66], LuPO 4 [67], and Sr 3 AlSi 1− x O 5 [68]. In all those cases, the position of the maximum of the glow peak could be connected to the trap depth.…”

Fabricated CeO2 nanopowders as a novel sensing platform for advanced forensic, electrochemical and photocatalytic applications

“…Figure 15a shows the PL emission spectra of asformed CeO 2 NPs prepared with various fuel concentration under k Exc = 386 nm. The spectra exhibits peaks at * 362, 391 and 441 nm may be attributed to surface defects, charge transition from the 4f band to the valence band of CeO 2 and oxygen vacancies (Li et al 2008;Dang et al 2010;Luo et al 2015). The emission spectra of calcined CeO 2 NPs excited under 386 nm wavelength as shown in Fig.…”

Toward tunable and bright deep‐red persistent luminescence of Cr3+ in garnets

“…As mentioned in the Introduction, codoping strategy using lanthanide ions as additional electron traps has been widely used to further enhance the PersL intensity of persistent phosphors. 3,25,27,28 However, considering fabricating at least 15 different codoping samples with different lanthanide codopants as a trial and error method for one target host, which is an inefficient approach relying on serendipity, employ theoretical predictions, especially energy-level locations of lanthanide ions in the target host is a much more efficient way to realize this purpose. Therefore, we again take the GSGG:Cr sample as a typical example to demonstrate how to select suitable lanthanide ions as sensitizers by utilizing the HRBE diagram as a highly efficient prediction tool.…”

“…Therefore, once the binding energy of the 4 f ground state (GS) for one lanthanide ion relative to the conduction band (CB) or the valence band (VB) is determined, those of 4 f levels of all other lanthanides in a certain material host can be estimated fairly well by constructing either host‐referred binding energy (HRBE) or vacuum‐referred binding energy (VRBE) diagrams . Since lanthanide ions are widely adopted as electron trap centers (hole trap centers in rare cases) for developing novel persistent phosphors or enhancing PersL intensities in present/reported persistent phosphors, these theoretical prediction diagrams can be a very useful guide to choose proper lanthanide ions as efficient foreign traps inducing desirably long PersL …”

“…[22][23][24] Since lanthanide ions are widely adopted as electron trap centers (hole trap centers in rare cases 25,26 ) for developing novel persistent phosphors or enhancing PersL intensities in present/reported persistent phosphors, these theoretical prediction diagrams can be a very useful guide to choose proper lanthanide ions as efficient foreign traps inducing desirably long PersL. 3,22,25,27,28 In this work, photoluminescence (PL), PersL, and thermoluminescence (TL) properties of six different garnets are investigated in detail, and we introduce a facile way to develop Cr 3+ -doped garnet persistent phosphors using both the crystal field engineering to tune the emission band of Cr 3+ The starting powder was mixed by a ball milling method with anhydrous alcohol for 1 hour. The mixed powder was dried at 80°C for 36 hours, compacted to form a ceramic green body under uniaxial pressing of 50 MPa, and finally sintered at 1600°C for 10 hours in air.…”