Photoluminescence of layered perovskite oxides with triple-octahedra slabs containing titanium and niobium

摘要

Study of the photochemical properties of layered compounds can be expected to lead us to the development of new photofunctional materials [1]. Various oxides with layered perovskite structures have been synthesized as layered compound groups [2-4]. Dion-Jacobson (K2-xLa2Ti3-xTNbx O10, etc.) [2,3] and Ruddlesden-Popper (K2-xLa2Ti3-xTNbx O10, etc.) [4(b)] series are the representative layered perovskite oxides containing titanium and niobium. Recently, Gopa-lakrishnan et al. have synthesized bridging compounds of Dion-Jacobson and Ruddlesden-Popper phases (K2-xLa2Ti3-xTNbx O10) [4(c)]. They consist of three-octahedral thick perovskite slabs. It has been reported that some layered perovskite oxides which consist of titanium and niobium oxides work as photofunctional materials such as photocatalysts [5] and phosphors [6]. Moreover, they seem to be interesting as hosts of lanthanoid phosphors since many layered perovskite oxides contain lanthanum ions [7-9]. In these systems, the energy transfer process from hosts (layered oxides) to guests (lanthanoid ions) is important. Therefore, it is important to study the luminescent properties of native layered oxides to obtain basic data on their photophysical and photochemical properties. This communication reports the luminescent properties of a series of layered perovskite oxides with three-octahedral thick perovskite slabs (K2-xLa2Ti3-xTNbx O10(x = 0, 0.25, 0.5, 0.75, and 1) and KM2Nb3Oi0 (M = Ca and Sr)).