Effect of kaolinite edge surfaces on formation of Tb³⁺-doped phosphor by solid-state reaction

Abstract

The effect of kaolinite edge surfaces on a solid-state reaction was demonstrated by the synthesis of Tb3+-doped metastable CaAl2Si2O8, indicating the importance of Tb3+ adsorbed on kaolinite edge surfaces.

Assessment of the Crystallization Process of CaO–Al2O3–SiO2 Glass Probed with Tb3+ Luminescence

“…Recently, Tb 3+ was successfully accommodated into metastable CaAl 2 Si 2 O 8 , and the resulting Tb 3+ -doped material produced a fluorescence spectrum having a relatively small B/G ratio. 31 The B/G ratio for the CAS-1.48Tb-8 h in Figure 5 is slightly below the dotted line that shows the relationship between the B/G ratio and Tb 2 O 3 content as estimated using Tb 3+ -doped glass specimens before crystallization. Thus, the effect of Tb 3+ accommodation into metastable CaAl 2 Si 2 O 8 on the B/G ratio is minute when working with the volume fraction range assessed in this study.…”

“…In the case of the fluorescence spectrum obtained from the CAS-1.48Tb-8 h prior to normalization (Figure ), the luminescence due to the 5 D 4 – 7 F 6 transition appears as very weak shoulders at shorter wavelengths. Recently, Tb 3+ was successfully accommodated into metastable CaAl 2 Si 2 O 8 , and the resulting Tb 3+ -doped material produced a fluorescence spectrum having a relatively small B/G ratio . The B/G ratio for the CAS-1.48Tb-8 h in Figure is slightly below the dotted line that shows the relationship between the B/G ratio and Tb 2 O 3 content as estimated using Tb 3+ -doped glass specimens before crystallization.…”

Effect of carbon on the co-presence of metallic tungsten as a nucleation agent and Eu2+ in glass: crystallization of CaO–Al2O3–SiO2 glass probed with Eu2+ luminescence

“…Notably, the solid-state reaction of kaolinite with CaCO 3 forms metastable CaAl 2 Si 2 O 8 at 900 °C under air but unfortunately generates anorthite (CaAl 2 Si 2 O 8 ) under a reductive atmosphere despite the 900 °C reaction temperature. 30 The preparation of Eu 2+ -doped metastable CaAl 2 Si 2 O 8 could thus be the topic of a future study.…”

“…, a reductive atmosphere) at 900 °C for 12 h. 29,30 Notably, the solid-state reaction of kaolinite and CaCO 3 forms anorthite (CaAl 2 Si 2 O 8 ) and metastable CaAl 2 Si 2 O 8 depending on the reaction temperature and atmosphere. 30 The obtained product was thus denoted as Eu 2+ –CaAl 2 Si 2 O 8 for convenience.…”

Comparison of microscopic adsorption characteristics of Zn(II), Pb(II), and Cu(II) on kaolinite

“…Zn(II), Pb(II), and Cu(II) ions do not have adequate capacity to break these H-bonds 36 ; therefore, metal ions could rarely enter the inter layer spaces. Besides, kaolinite is known to have negligible isomorphic substitution 37 , 38 . Thus, the adsorption performance of kaolinite can be improved through intercalation to increase the interval between layers.…”