Crystal structure and Luminescence Properties of Sr2Al6O11:Eu2+.

Abstract

SYNOPSIS Eu2+activated Sr2Al6O11 and Sr4Al14O25 were prepared with B2O3 additives at the temperatures of 1100•Ž to 1300•Ž in flowing 5% H2/Ar gas. These products were characterized by XRD analysis, UV and VUV spectroscopy and so forth. The precise crystal structure of Sr2Al6O11 was first determined by Rietveld method. Between the sheets of the edge shared AlO6 octahedron, the corner shared AlO4 tetrahedral linkages of Sr2Al6O11 demonstrated a quite different fashion than that of Sr4Al14O25 According to the UV-Vis. and VUV spectra, an intense broad emission was observed near 460 nm in Sr2Al6O11:Eu2+, and two emission peaks were recognized at 409 nm and 496 nm in Sr4Al14O25:Eu2+.

Synthesis, luminescence and persistent luminescence of europium-doped strontium aluminates

“…S2A3 is obtained only by solid state synthesis in the presence of boron oxide under specific conditions. Takeda et al [56] report that at 1473 K, S2A3 is formed predominantly with a boron to aluminum ratio of 0.05. With lower boron content, SA and Al2O3 are found, while with a ratio of 0.1, the formation of S4A7 dominates.…”

“…𝐸 𝑒𝑚 = 𝐸 𝑓𝑟𝑒𝑒 − 𝐷 − 𝛥𝑆 where ΔS is the Stokes shift. combined with the results for S2A3 [56], and S4A [97] and others, are compiled in the Table 6. All these emission bands have lifetimes around 1 μs which are typical for Eu 2+ f-d transitions [144].…”

“…If one associates the extinction coefficient with the radiative lifetime (ca 1 μs for Eu 2+ and 1 ms for Eu 3+ ), then already 5-10% of Eu 2+ can mask the emission of Eu 3+ . Heating SA3:Eu 2+ in air at 773 K leads to ca 50% reduction in emission intensity, while for S4A7:Eu 2+ , the same treatment yield no intensity reduction[56]. The presence of boron can prevent the oxidation of Eu 2+ in air.…”

Self-Propagating Combustion Synthesis, Luminescent Properties and Photocatalytic Activities of Pure Ca12Al14O33: Tb3+(Sm3+)

“…For example, high-efficiency green MgAl 11 O 19 : Ce 3+ , Tb 3+ (Jung et al, 2005) and blue BaMgAl 10 O 17 : Eu 2+ (Kim et al, 2002) luminescent powders used Mg(Ba)O-Al 2 O 3 as hosts had widely been applied in the world. Also, there are many reports on the blue-luminescent materials using SrO-Al 2 O 3 system as hosts, including Sr 2 Al 6 O 11 (Takeda et al, 2002), Sr 4 Al 14 O 25 (Garcia et al, 2016), SrAl 2 O 4 (Sohn et al, 2002), and SrAl 4 O 7 (Singh et al, 2016), etc., as well as red-luminescent materials using LiAlO 2 (Lee et al, 2012), LiAl 5 O 8 (Singh and Rao, 2008), and CaAl 12 O 19 (Brik et al, 2011) as hosts. However, many of above materials are prepared by the traditional solid phase calcined method, which has the obvious deficiency of energy consumption because of high synthesis temperature.…”

Intrinsic Defects in Strontium Aluminates studied via Computer Simulation Technique

“…Sr 4 Al 14 O 25 [7] and Sr 2 Al 6 O 11 [8] exist in orthorhombic phase, while the Sr 3 Al 2 O 6 [9] and Sr 9 Al 6 O 18 [10] exists in cubic phase. The hexagonal phase is observed in Sr 7 Al 12 O 25 [11] and SrAl 12 O 19 [12], and monoclinic phase is observed for SrAl 4 O 7 [13] and Sr 10 Al 6 O 19 [14].…”