Eu3+-Doped glass ceramics containing NaTbF4 nanocrystals: controllable glass crystallization, Tb3+-bridged energy transfer and tunable luminescence

Abstract

Herein, hexagonal and cubic NaTbF₄:Eu³⁺ nanocrystals embedded in transparent glass ceramics were successfully synthesized via a conventional melt-quenching technique followed by glass crystallization for the first time. Structural and spectroscopic characterizations evidenced the composition-dependent crystalline precipitation and the partition of Eu³⁺ dopants into the NaTbF₄ host. In particular, the energy transfer mechanism from Tb³⁺ to Eu³⁺ was systematically investigated by photoluminescence spectra and decay curves, confirming that the energy transfer chain of Tb³⁺ → (Tb³⁺)_n → quenchers in NaTbF₄ nanocrystals was replaced by Tb³⁺ → (Tb³⁺)_n → Eu³⁺ with the incorporation of Eu³⁺. The discrepant luminescence behaviors in terms of on-phase transformation were also studied. Furthermore, tunable emission could be achieved by merely adjusting the content of Eu³⁺, producing distinguishable emissions. As a consequence, it could be expected that NaTbF₄:Eu³⁺ nanocrystals embedded in glass ceramics are promising candidates for applications in lightings and displays.