Enhanced luminescence of Tb3 + due to efficient energy transfer fromCe3 + in ananocrystalline Lu2Si2O7 host lattice

Abstract

Nanocrystalline lutetium pyrosilicateLu2Si2O7 (LPS) doped withTb3 + (LPS:Tb) orCe3 + /Tb3 + (LPS:Ce, Tb) was obtainedat 1250 °C by the reactionof nanostructured Lu2O3 and colloidal SiO2. X-ray diffraction analysis confirmed the crystallization of a single phase of LPS at the indicatedtemperature. Different concentrations of active ions allowed us to study the influence ofCe3 + co-dopingon Tb3 + emission. Tb3 + -doped LPS yields both the blue emission (J = 3, 4, 5, 6) and the green emission (J = 3, 4, 5, 6) ofTb3 + . The greenemission of Tb3 + is enhanced remarkably in both the cathodoluminescence andphotoluminescence spectra because of energy transfer fromCe3 + toTb3 + ions, both of which are present in the host lattice. Based on theoptical luminescence and luminescence excitation spectra, the optimalTb3 + doping level for maximum light output was established to be 9 mol% and the highest enhancement ofTb3 + luminescence byCe3 + co-doping was detectedusing a 1:3 ratio of Ce3 + /Tb3 + concentration. Two different crystallographic sites ofTb3 + in the LPS lattice were detected in the luminescence and excitation spectra of samples with higherTb3 + concentrations (6–9 mol%). The single-exponential decay profile of 5D4 emission for the less concentrated samples and the double-exponential decay for the higherdoping level are in agreement with this observation. Calculation of colour coordinatesshows that LPS:Ce(0.25%)Tb(3%) emits white light.