Strontium aluminate

When activated with a suitable dopant (e.g. europium, written as Eu:SrAl2O4), it acts as a photoluminescent phosphor with long persistence of phosphorescence.

Strontium aluminates exist in a variety of other compositions including SrAl4O7 (monoclinic), Sr3Al2O6 (cubic), SrAl12O19 (hexagonal), and Sr4Al14O25 (orthorhombic).

The development of strontium aluminate pigments in 1993 was spurred on by the need to find a substitute for glow-in-the-dark materials with high luminance and long phosphorescence, especially those that used promethium.

This influences the wavelength of emission of the europium ion, by its covalent interaction with surrounding oxygens, and crystal field splitting of the 5d orbital energy levels.

Polycrystalline Mn:SrAl12O19 is used as a green phosphor for plasma displays, and when doped with praseodymium or neodymium it can act as a good active laser medium.

Slight modifications in the manufacturing process (the type of reducing atmosphere, small variations of stoichiometry of the reagents, addition of carbon or rare-earth halides) can significantly influence the emission wavelengths.

A small amount of silicon substituting the aluminium can increase emission intensity by about 5%; the preferred composition of the phosphor is Ce0.15Mn0.15:SrAl11Si0.75O19.

[8] However, the material has high hardness, causing abrasion to the machinery used in processing it; manufacturers frequently coat the particles with a suitable lubricant when adding them to a plastic.

[9] Strontium aluminates have been examined as proposed materials for immobilization of fission products of radioactive waste, namely strontium-90.

[11] Strontium aluminate based afterglow pigments are marketed under numerous brand names such as Core Glow, Super-LumiNova[12] and Lumibrite, developed by Seiko.

[13] Companies offer an industrial marble aggregate mixed with the strontium aluminate, to enable ease of using within standard construction processes.

Cubic strontium aluminate can be used as a water-soluble sacrificial layer for the production of free-standing films of complex oxide materials.

Europium doped strontium silicate-aluminate oxide powder under visible light, long-wave UV light, and in total darkness.
Europium doped strontium silicate-aluminate oxide powder under visible light, long-wave UV light, and in total darkness.
Green (emission at 515 nm) C3 Super-LumiNova applied on a diver's watch to make it readable in low light conditions.
Blue-green (emission at 485 nm) BGW9 Super-LumiNova applied on a similar diver's watch face.
Reusable and non-toxic glow stick made from strontium aluminate particles mixed with a settable material. The different colours are made from slightly different strontium aluminate formulas.