On the photoluminescence of multi-sites Ce³⁺ in T-phase orthosilicate and energy transfer from Ce³⁺ to Tb³⁺

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>Ce<SUP>3+</SUP>, Tb<SUP>3+</SUP> co-doped T-phase orthosilicate Ba<SUB>1.2</SUB>Ca<SUB>0.8</SUB>SiO<SUB>4</SUB> phosphors were prepared by means of solid state reactions. The synthesized samples were investigated using XRD and PL emission and excitation spectra. The emission spectra for Ce<SUP>3+</SUP> doped Ba<SUB>1.2</SUB>Ca<SUB>0.8</SUB>SiO<SUB>4</SUB> phosphors show broad bands in the 320–550 nm spectral region. The excitation spectra exhibit several absorption peaks in the range of 250–400 nm. Both the emission and excitation spectra are dependent on the excitation or monitoring wavelengths. We attribute these results to Ce<SUP>3+</SUP> ions occupying two different crystallographic sites (i.e., Ce I and Ce II). The Ce<SUP>3+</SUP>, Tb<SUP>3+</SUP> co-doped Ba<SUB>1.2</SUB>Ca<SUB>0.8</SUB>SiO<SUB>4</SUB> phosphors show Tb<SUP>3+</SUP>-related line emissions in the 475–600 nm spectral region and Ce<SUP>3+</SUP>-related band emissions in the 350–525 nm spectral region when the 4<I>f</I> → 5d transition of Ce<SUP>3+</SUP> is excited (λ<SUB>ex</SUB> = 345 nm), indicating that energy transfer from Ce<SUP>3+</SUP> to Tb<SUP>3+</SUP> takes place. Moreover, the emission intensity of <SUP>5</SUP>D<SUB>4</SUB> → <SUP>7</SUP>F<SUB>5</SUB> transition for Ba<SUB>1.00</SUB>Ce<SUB>0.02</SUB>Tb<SUB>0.08</SUB>Li<SUB>0.10</SUB>Ca<SUB>0.8</SUB>SiO<SUB>4</SUB> is 30 times stronger than that of Ba<SUB>1.04</SUB>Tb<SUB>0.08</SUB>Li<SUB>0.08</SUB>Ca<SUB>0.8</SUB>SiO<SUB>4</SUB> sample under 345-nm UV excitation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PL spectra are dependent on excitation or monitoring wavelengths. </LI> <LI> Ce<SUP>3+</SUP> ions occupy two different crystallographic sites (i.e., Ce I and Ce II). </LI> <LI> Efficient energy transfer from Ce<SUP>3+</SUP> to Tb<SUP>3+</SUP> takes place. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>