Achieving efficient Tb3+ dual-mode luminescence via Gd-sublattice-mediated energy migration in a NaGdF4 core–shell nanoarchitecture

Abstract

A strategy to realize dual-mode luminescence from identical Tb³⁺ is provided via Gd-sublattice-mediated energy migration and core–shell engineering techniques. By optimizing the structure of a NaGdF₄:Yb/Tm@NaGdF₄:Ce/Tb nanoarchitecture, both upconversion and downshifting emissions, originating from ⁵D₄ → ⁷F_6,5,4,3 transitions of Tb³⁺, are achieved through Yb³⁺ → Tm³⁺ → [Gd³⁺]_n → Tb³⁺ and Ce³⁺ → [Gd³⁺]_n → Tb³⁺ energy transfer processes, respectively.