Cooperative Energy Transfer Up-Conversion and Quantum Cutting Down-Conversion in Yb³⁺:TbF₃ Nanocrystals Embedded Glass Ceramics

Abstract

Yb 3+ -doped oxyfluoride glass ceramics were fabricated by melt-quenching and subsequent heating. X-ray diffraction and high-resolution transmission electron microscopy analyses evidenced that orthorhombic TbF 3 nanocrystals with a mean size of 22 nm were homogeneously precipitated among the aluminosilicate glass matrix. The incorporation of Yb 3+ ions into TbF 3 crystals was confirmed by energy-dispersive X-ray spectroscopy. Under 976 nm near-infrared laser excitation, the glass ceramics exhibited intense green Tb 3+: 5 D 4 → 7 F J ( J = 3, 4, 5, 6) up-conversion luminescence due to the cooperative energy transfer from two Yb 3+ ions to one Tb 3+ ion. In comparison, under 485 nm excitation, they yielded near-infrared quantum cutting down-conversion emission corresponding to Yb 3+: 2 F 5/2 → 2 F 7/2 transition, ascribing to the cooperative energy transfer from one Tb 3+ ion to two Yb 3+ ions. The energy transfer processes between Tb 3+ and Yb 3+ ions were discussed, and the energy transfer efficiency was evaluated.