Enhancement of Host Excitation-Mediated Photoluminescence and Preferential Quenching of Direct Photoactivator Excitation-Mediated Photoluminescence by Exfoliation of Layered KLa_(0.90)Sm_(0.05)Nb2O7 into La_(0.90)Sm_(0.05)Nb2O7 Nanosheets

摘要

The bulk layered compound KLa_(0.90)Sm_(0.05)Nb2O7 and its exfoliated form of La_(0.90)Sm_(0.05)Nb2O7 nanosheet have been prepared, and their photoluminescence properties have been characterized. The photoluminescence emission of KLa_(0.90)Sm_(0.05)Nb2O7 via host excitation is negligibly low in intensity, whereas the emission via direct Sm~(3+) excitation has apparently been observed. On the contrary, the emission via direct Sm~(3+) excitation is preferentially quenched, and the emission via host excitation becomes far more predominant than that via direct Sm~(3+) excitation for the exfoliated La_(0.90)Sm_(0.05)Nb2O7 nanosheet. From the comparison of photoluminescence properties between the bulk layered compound KLa_(0.90)Sm_(0.05)Nb2O7 and its exfoliated form of La_(0.90)Sm_(0.05)Nb2O7 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.