Eu2+ doped calcium aluminate coatings by sol–gel methods

Eu 2+ doped calcium aluminate coatings were prepared by the dip- and spin-coating methods on α-alumina substrates. This kind of persistent luminescent coatings may replace the luminous paints used in many applications. If sol-gel methods are used the expense of preparing the coatings is relatively low. Annealing at 1050 °C yielded the CaAl 2 O 4 :Eu 2+ coatings with similar luminescence and thermoluminescence properties than those of the CaAl 2 O 4 :Eu 2+ powders. At higher annealing temperatures, CaAl 4 O 7 and CaAl 12 O 19 were formed due to the diffusion of alumina from the substrate. The persistent luminescence was, however, relatively weak and thus more work is needed to optimize the multitude of parameters affecting the properties of the coatings.