The SrA1₂O₄ phosphor has been accepted as one of the most important persistent luminescent materials, due to the wide excitation spectrum, visible emission spectrum range, high luminescent intensity, long afterglow duration. This kind of material has been applied in painting, plastics, construction as pigments for safety and security purposes, as well as sensors for structural damage, fracture of materials. However it is easy to hydrolyze in the moist place. The luminescent ability of the material will degrade continually with the hydrolysis reaction proceeding, and finally this optical ability will disappear which makes the material useless. To overcome the problem of hydrolysis, a surface modification is applied in this project.

One A2B3 hyperbranched polymerization method...[ Read more ]

The SrA1₂O₄ phosphor has been accepted as one of the most important persistent luminescent materials, due to the wide excitation spectrum, visible emission spectrum range, high luminescent intensity, long afterglow duration. This kind of material has been applied in painting, plastics, construction as pigments for safety and security purposes, as well as sensors for structural damage, fracture of materials. However it is easy to hydrolyze in the moist place. The luminescent ability of the material will degrade continually with the hydrolysis reaction proceeding, and finally this optical ability will disappear which makes the material useless. To overcome the problem of hydrolysis, a surface modification is applied in this project.

One A2B3 hyperbranched polymerization method was conducted in the surface modification, and one layer of polymer coating with abundant hydrophobic groups was obtained to keep the inner phosphors from degradation. The synthesized polymer coating layers were characterized by FTIR, TGA, EDS, SEM, and TEM. Their chemical component was proved and the layer thickness was measured.

Five different coating products were synthesized with the thickness from 100 nm to 550 nm. These thicker organic coating layers were obtained by solving the problem of low grafting density during the polymerization. Due to these polymer coating layers, the water resistance of aluminate phosphors had been improved a lot, compared with the untreated phosphor. Meanwhile, the comparison experiments showed the persistent luminescence intensity would decrease with the thickness increase of coated polymer layers, due to the energy dissipation in the organic layer.