Enhanced luminescence of Tb3 +due to efficient energy transfer from Ce3 +in a nanocrystalline Lu2Si2O7host lattice

Nanocrystalline lutetium pyrosilicate Lu(2)Si(2)O(7) (LPS) doped with Tb(3+) (LPS:Tb) or Ce(3+)/Tb(3+) (LPS:Ce, Tb) was obtained at 1250 °C by the reaction of nanostructured Lu(2)O(3) and colloidal SiO(2). X-ray diffraction analysis confirmed the crystallization of a single phase of LPS at the indicated temperature. Different concentrations of active ions allowed us to study the influence of Ce(3+) co-doping on Tb(3+) emission. Tb(3+)-doped LPS yields both the blue emission [Formula: see text] (J = 3, 4, 5, 6) and the green emission [Formula: see text] (J = 3, 4, 5, 6) of Tb(3+). The green emission of Tb(3+) is enhanced remarkably in both the cathodoluminescence and photoluminescence spectra because of energy transfer from Ce(3+) to Tb(3+) ions, both of which are present in the host lattice. Based on the optical luminescence and luminescence excitation spectra, the optimal Tb(3+) doping level for maximum light output was established to be 9 mol% and the highest enhancement of Tb(3+) luminescence by Ce(3+) co-doping was detected using a 1:3 ratio of Ce(3+)/Tb(3+) concentration. Two different crystallographic sites of Tb(3+) in the LPS lattice were detected in the luminescence and excitation spectra of samples with higher Tb(3+) concentrations (6-9 mol%). The single-exponential decay profile of (5)D(4) emission for the less concentrated samples and the double-exponential decay for the higher doping level are in agreement with this observation. Calculation of colour coordinates shows that LPS:Ce(0.25%)Tb(3%) emits white light.