Simultaneous Spectral Tuning and Thermal Stability Adjustment in Ca₈ZnGa_{(1–<i>x</i>)}La_<i>x</i>(PO₄)₇:Eu²⁺ Phosphors

Abstract

The modifications of local structure in solid solution are a crucial step to regulate the photoluminescence properties of rare-earth ion-based phosphors. However, the structural diversity of host matrices and the uncertain occupation of activators make it challenging to obtain phosphors with both high stability and tailored emission. Herein, We synthesized a series of β-Ca₃(PO₄)₂-type Ca₈ZnGa_(1-<i>x</i>)La_<i>x</i>(PO₄)₇:Eu²⁺ solid solution phosphors by design. By modifying the Ga/La ratio, controllable regulation of the emission spectrum and thermal stability of the phosphors can be achieved at the same time. The introduction of La³⁺ can regulate the crystal field splitting strength of the Eu²⁺ activators, causing redshifts in the emission spectrum while increasing Ga³⁺ content will lead to enhanced energy transfer between the oxygen vacancy and Eu²⁺, as well as improved thermal stability. Through local structure modification, the spectrum and thermal stability of phosphors can be facilely tuned. The results indicate that this series of phosphors have versatile potentials in various applications.