Controlled synthesis and photoluminescence properties of Bi2SiO5:Eu3+ core-shell nanospheres with an intense 5D0→7F4 transition

Core-shell Bi2SiO5 nanosystem with uniform morphology and narrow size distribution has been successfully synthesized via a facile template-assisted route. With the introduction of Eu3+, detailed studies are performed to evaluate its promise as Eu3+-based phosphor host. The yielded Bi2SiO5:Eu3+ nanospheres are proven to be pure tetragonal phase via X-ray diffraction and Rietveld refinement. Moreover, the phosphor particles consist of monodisperse spheres with an average diameter of approximately 285 nm by high-resolution electron microscopy. When excited by near-ultraviolet (NUV) light, the abnormally high-intensity emission at 703 nm arising from the 5D0→7F4 transition of Eu3+ is observed. The temperature-dependent photoluminescence spectra show that the optimized Bi2SiO5:20%Eu3+ have satisfactory thermal stability with 63.7% of emission intensity at 423 K relative to 303 K. The deep-red light-emitting diode (LED) device fabricated by coating NUV chip with the Bi2SiO5:20%Eu3+ phosphors is demonstrated. The newly-developed Bi2SiO5:Eu3+ nanophosphors display commendable photoluminescence properties, demonstrating their promise as deep-red phosphor candidates for use in phosphor-converted LEDs.