Design, synthesis and characterization of an orange-yellow long persistent phosphor: Sr_3Al_2O_5Cl_2:Eu^2+,Tm^3+

Abstract

A novel orange-yellow emitting Sr3Al2O5Cl2:Eu(2+), Tm(3+) phosphor with bright and long persistent luminescence (LPL) has been newly developed. The incorporation of Tm(3+) into the Sr3Al2O5Cl2:Eu(2+) as an auxiliary activator dominates its long persistent luminescence and thermoluminescence characteristics to a large extent. The emissions in Sr3Al2O5Cl2:Eu(2+), Tm(3+) for both fluorescence and LPL are due to the 5d → 4f transitions of Eu(2+). The orange-yellow long persistent luminescence with the chromaticity coordination of (0.53, 0.46) can persist for nearly 220 min at recognizable intensity level (≥ 0.32 mcd/m2). This investigation provides a new and efficient long persistent phosphor which enriches the color of the existing LPL.

Luminescent properties of blue green Sr3Al2O5Cl2:Pr3+ and orange red Sr3Al2O5Cl2:Eu2+, Pr3+ afterglow phosphors

“…Fortunately, in our work we have synthesized the orange red Eu 2+ -doped Sr 3 Al 2 O 5 Cl 2 phosphors at a relative lower temperature (~800 o C) than the former reports (~1250 o C) (Tang et al, 2008;Song et al, 2009;Zhang et al, 2009a;Zhang et al, 2009b;Zhang et al, 2010;Wang et al, 2012;Dutczak et al, 2013;Li et al, 2010), and its afterglow can be seen in the dark approaching to 180 minutes. In the Sr 3 Al 2 O 5 Cl 2 :Eu 2+ , Ce 3+ phosphor, the energy transfer from the Ce 3+ to Eu 2+ ions was observed, and in the incorporation of Ce 3+ could significantly prolong the afterglow duration of Sr 3 Al 2 O 5 Cl 2 : Eu 2+ phosphor (Chen et al, 2014).…”

“…However, discussion about the afterglow property of Eu 2+ -doped and rare-earth co-doped Sr 3 Al 2 O 5 Cl 2 was seldom, and the few examples of them were Sr 3 Al 2 O 5 Cl 2 : Eu 2+ , Dy 3+ (Dutczak et al, 2013) and Sr 3 Al 2 O 5 Cl 2 : Eu 2+ , Tm 3+ (Li et al, 2010). Moreover, in the report of D. Dutczak et al, …”

Persistence energy transfer between inequivalent Eu2+ ions in CaAl2Si2O8:Eu2+

“…4 are tentatively assigned to the oxygen vacancies' related glow bands. The optimized TL band is situated slightly above room temperature (around 350 K) for better afterglow properties [14]. Therefore, the band at 325 K in CaAl 2 Si 2 O 8 :Eu 2+ could be responsible for the phosphorescence.…”

Luminescent properties of a green emitting persistent phosphor CdGeO3:Tb3+

“…At present, the yellow-green, green-blue, and blue persistent phosphors with high brightness and long afterglow time have been available in the commercial market [2][3][4]. In addition to sulfides (CaS:Eu 2+ , Tm 3+ , red) [5], oxysulfides (Y 2 O 2 S:Eu 3+ , Ti 4+ , Mg 2+ , red) [6], and nitrides (Ca 2 Si 5 N 8 :Eu 2+ , Tm 3+ , orange) [7], a few orange-red persistent phosphors have been reported such as CaTiO 3 :Tb 3+ [8], Ca 2 SnO4:Sm 3+ [9], and S r3 Al 2 O 5 Cl 2 :Eu 2+ , Tm 3+ [10]. Recently, the advanced persistent phosphors have attracted considerable attention due to the demands for new applications in the medical field such as cancer photodynamic therapy, cancer diagnoses and in vivo imaging except for the traditional domain including emergency signalization, solar energy utilization, image storage, and thermal sensors [11][12][13][14][15][16][17].…”