Tunable Luminescence and Energy Transfer in Novel Blue-Green-Emitting BaGd₂Si₃O₁₀:Ce³⁺,Tb³⁺ Phosphors for Near-UV-Based White LEDs

A new series of Ce3+ singly doped and Ce3+/Tb3+-co-doped BaGd2Si3O10 (BGSO) phosphors have been synthesized by a high-temperature solid-state reaction technique. The phase purity, luminescence properties, energy transfer mechanism, internal quantum efficiency, and thermal stability of as-prepared phosphors were investigated in detail. The photoluminescence spectra of BGSO:xCe3+ phosphors exhibited broad emission in the wavelength range of 350–600 nm with a peak maximum at 427 nm. Under 336 nm excitation, the tunable blue-green luminescence of BGSO:0.04Ce3+,yTb3+ phosphors was investigated as a function of Tb3+ concentration and well demonstrated by the energy transfer mechanism from Ce3+ to Tb3+ ions. The critical distance (Rc) of energy transfer was estimated using concentration quenching method, and its value was found to be 10.75 Å. The thermal stability and activation energy of thermal quenching were analyzed for composition-optimized BGSO:0.04Ce3+,0.30Tb3+ phosphors by varying the temperature from 303 to 483 K. The results obtained from the present investigation suggested that Ce3+- and Ce3+/Tb3+-activated BGSO phosphors can serve as promising materials for near-UV-based phosphor-converted white light-emitting diodes.