Enhancement of Host Excitation-Mediated Photoluminescence and Preferential Quenching of Direct Photoactivator Excitation-Mediated Photoluminescence by Exfoliation of Layered KLa0.90Sm0.05Nb2O7 into La0.90Sm0.05Nb2O7 Nanosheets

The bulk layered compound KLa0.90Sm0.05Nb2O7 and its exfoliated form of La0.90Sm0.05Nb2O7 nanosheet have been prepared, and their photoluminescence properties have been characterized. The photoluminescence emission of KLa0.90Sm0.05Nb2O7 via host excitation is negligibly low in intensity, whereas the emission via direct Sm3+ excitation has apparently been observed. On the contrary, the emission via direct Sm3+ excitation is preferentially quenched, and the emission via host excitation becomes far more predominant than that via direct Sm3+ excitation for the exfoliated La0.90Sm0.05Nb2O7 nanosheet. From the comparison of photoluminescence properties between the bulk layered compound KLa0.90Sm0.05Nb2O7 and its exfoliated form of La0.90Sm0.05Nb2O7 nanosheet, the relative enhancement of the host excitation-mediated photoluminescence by exfoliation of bulk Ln-photoactivated layered phosphors into nanosheets as a general trend has become more apparent.