Abstract
We report on the transformation of nanoporous -alumina particles into the spinel type ZnAl2O4 without notably deteriorating the porosity of the host material. This was carried out by depositing thin layers of ZnO by the technique of atomic layer deposition (ALD) and subsequently annealing the sample at 800°C to facilitate a solid state reaction inducing the formation of the spinel phase. Such particles represent robust and inert structures, most suitable as host materials for catalysis; and other processes where a large surface area is desired. The samples with the Spinel structure were used as host materials for a red-emitting phosphor by depositing a thin layer of europium on the surface of the particles, also by the ALD technique. The rare earth coating was restricted to the surface of the porous spinel, due to reaction kinetics; a strong luminescence at 620 nm was consequently observed. The synthesis and characterization of all these structures are described in this work.
