Tunable green/red dual-mode luminescence via energy management in core-multishell nanoparticles

Publication date: 15 August 2018
Source:Materials & Design, Volume 152
Author(s): Zhihua Leng, Liping Li, Dan Zhang, Guangshe Li
Achieving up-conversion luminescence from Tb³⁺/Eu³⁺ ions was generally via a complicated energy transfer process (Yb³⁺ → Tm³⁺ → Gd³⁺ → Ln³⁺, Ln = Tb/Eu), which makes the relevant energy management rather difficult and inevitably results in impure blue luminescence of Tm³⁺. In this work, a facile and rational strategy is designed to integrate dual-mode luminescence from Eu³⁺/Tb³⁺ ions into NaGdF4:Yb/Eu@NaGdF4:Ce@NaGdF4:Yb/Tb@NaYF4 core-multishell nanostructure. It is found that the down-conversion energy transfer across NaGdF4@NaGdF4 interface is confined in a narrow space region of approximately 2 nm. For the up-conversion mode, the primary factor that dominates the emission intensity of Eu³⁺ is determined to be the molar ratio of NaGdF4:Yb/Tb component in the second shell to NaGdF4:Yb/Eu one in the core, which differs from the anisotropic filtration effect previously reported. Eventually, tunable dual-mode emission colors were achieved through simply varying the inner shell thickness of NaGdF4:Yb/Tb. The strategy of integrating dual-mode luminescence of Eu³⁺/Tb³⁺ reported here for energy management allows one to design new luminescence materials for many important applications.

Graphical abstract

https://ift.tt/2KDYBM8