Comparison of the photoluminescence properties and thermal stability of the metal ions Pb2+, Bi3+ and the rare earth ions Eu3+, Tb3+ activated in the silicate-based single phosphor for solid-state applications
摘要
A series of Ba₂CaZn₂Si₆O₁₇ (BCZSO) silicate phosphors, emitting a broad spectrum of visible light including deep blue, blue, green, and red, were successfully synthesized by doping with Pb2+, Bi3+, Tb3+, and Eu3+ ions via a conventional solid-state reaction method. Powder X-ray diffraction (PXRD) analysis confirmed the formation of a single-phase orthorhombic structure, while scanning electron microscopy (SEM) revealed irregular morphologies indicative of typical high-temperature synthesis. Photoluminescence (PL) and excitation spectra demonstrated distinct emission features for each dopant, with optimal doping concentrations found to be 7 mol% for Pb2+, 3 mol% for Bi3+, 10 mol% for Tb3+, and 9 mol% for Eu3+. Corresponding critical transfer distances (Rc) were calculated as 29.32 Å (Pb2+), 23.05 Å (Bi3+), 19.6 Å (Tb3+), and 20.3 Å (Eu3+), highlighting unique energy transfer behaviors. Increasing dopant content resulted in shorter luminescence lifetimes, suggesting concentration quenching. Quantum efficiency and CIE chromaticity coordinates were evaluated, while thermal stability was verified through temperature-dependent PL (TDPL) analysis. The results affirm the potential of BCZSO-based phosphors for application in white light-emitting diodes (WLEDs), offering tunable emission, stability, and efficiency across the visible range.