SiO₂:Tb³⁺@Lu₂O₃:Eu³⁺ Core–Shell Phosphors: Interfacial Energy Transfer for Enhanced Multicolor Luminescence

Abstract

Uniform and well-dispersed SiO2:x%Tb3+@Lu2O3:y%Eu3+ core–shell spherical phosphors were synthesized via a solvothermal method followed by a subsequent calcination process. The structure, phase composition, and morphology of the samples were studied by X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results showed that the Lu2O3:Eu3+ layer was evenly coated on the surface of SiO2:Tb3+ spheres and the shell thickness was about 45–65 nm. The PL spectra and fluorescence lifetimes of the samples were further studied. It was proved that the multicolor luminescence of the samples could be realized by changing the doping concentration ratio of Eu3+ or by changing the excitation wavelengths. Compared with SiO2@Lu2O3:3%Tb3+,6%Eu3+, SiO2:3%Tb3+@Lu2O3:6%Eu3+ showed stronger luminescence intensity, longer fluorescence lifetime, and higher energy transfer efficiency, which was attributed to the effective interfacial energy transfer, and the interfacial energy transfer mechanism from Tb3+ to Eu3+ was a dipole–dipole interaction mechanism. The XPS results indicated that the sample contained a high content of Si–O–Lu bonds, which proved that there was a strong interaction between the SiO2 core and the Lu2O3 shell, making the interfacial energy transfer possible. These results provided a new idea for luminescence enhancement and multicolor luminescence.

A Comparative Study of SiO2:Tb3+@Gd2O3:Eu3+ and Its Inverted Tb3+-Eu3+ Core–Shell Phosphors

“…Wang et al successfully synthesized TiO 2 : x %Eu 3+ @SiO 2 : y %Tb 3+ nanospheres and exhibited the fluorescence enhancement and lifespan extension of Eu 3+ ions due to IET. We have demonstrated SiO 2 : x %Tb 3+ @Lu 2 O 3 : y %Eu 3+ core–shell structure in the previous text, where sensitizers Tb 3+ in the core and activators Eu 3+ in the shell are spatially separated, which can enhance the luminescence intensity and energy transfer efficiency by the effective IET compared with SiO 2 @Lu 2 O 3 :Tb 3+ ,Eu 3+ . However, current researches mainly focus on the occurrence level of the IET phenomenon in core–shell structure, and the objects that are usually compared either do not have the core–shell structure or there is no occurrence of IET phenomenon .…”

Structural Design for Controlling the Lattice Strain Relaxation Process in TiO2/SiO2 Core–Shell Nanoparticles

“…The Si-8 core was prepared according to our previously reported procedure. 43 TEOS (4.5 mL) was added into a mixture of 62 mL of ethanol, 25 mL of H 2 O, 9 mL of ammonia (25 wt %) and corresponding amount of (Tb/Si molar ratio = 8%), which was continuously stirred throughout the process. After stirring for 4 h, the resulting Si-8 particles were centrifuged, washed three times with ethanol.…”

Novel Dual-Excitation and Dual-Emission Materials: Eu2+,Pb2+ Co-doped Core–Shell-Structured CaS@CaZnOS Phosphors and Their Application for Highly Efficient Photosynthesis of Plants

“…The BaGeF 6 :Mn 4+ @ PPG-NaGdF 4 :Dy 3+ core−shell-structured phosphor synthesized by Yu et al 28 can simultaneously emit blue and red light under UV excitation. Wang et al 29 also designed and synthesized a core−shell-structured phosphor, SiO 2 :Tb 3+ @ Lu 2 O 3 :Eu 3+ , with dual emission. In addition to the abovementioned inorganic DE 2 materials, there are many research reports focused on organic complexes or fluorescent dyes.…”

“…The BaGeF 6 :Mn 4+ @PPG-NaGdF 4 :Dy 3+ core–shell-structured phosphor synthesized by Yu et al can simultaneously emit blue and red light under UV excitation. Wang et al . also designed and synthesized a core–shell-structured phosphor, SiO 2 :Tb 3+ @Lu 2 O 3 :Eu 3+ , with dual emission.…”