Preparation and Characterization of the Eu³⁺ Doped Perovskite Nanosheet Phosphor: La_0.90Eu_0.05Nb₂O₇

Eu 3+ -doped perovskite nanosheets, La 0.90 Eu 0.05 Nb 2 O 7, have been prepared by the soft chemical exfoliation reaction of K 1− x H x La 0.90 Eu 0.05 Nb 2 O 7 with a tetrabuthylammonium hydroxide aqueous solution. The resulting colloidal La 0.90 Eu 0.05 Nb 2 O 7 nanosheet suspension exhibits photoluminescence emission from the 5 D 0 to 7 F J manifold transitions of Eu 3+ by either direct excitation of Eu 3+ or host excitation, whereas no host emission was observed at room temperature. In the case of the bulk precursors K 1− x H x La 0.90 Eu 0.05 Nb 2 O 7, the direct excitation yields more intense emission than the host excitation. On the contrary, the most intense emission from the La 0.90 Eu 0.05 Nb 2 O 7 nanosheets was observed by exciting at the broad excitation band maximum (353 nm). The difference in the photoluminescence properties between the La 0.90 Eu 0.05 Nb 2 O 7 nanosheets and their bulk precursors seems to be related to the dimensionality of these host structures and the confinement of the energy-transfer process between the host layer units and Eu 3+ activators.