Realizing emission color tuning, ratiometric optical thermometry and temperature-induced redshift investigation in novel Eu3+-doped Ba3La(VO4)3 phosphors

Abstract

Rare earth-doped Ba₃La(VO₄)₃ phosphors with tunable emitting colors were firstly explored and their photoluminescence properties were systematically investigated. The experimental results show that the Ba₃La(VO₄)₃ phosphors exhibit high-brightness self-activated emission and enable us to sensitize the luminescence of rare earth activators. Under near-ultraviolet (UV) excitation, both the broadband emission from VO₄³⁻ groups and the sharp peak emissions from Eu³⁺ ions are observed in Ba₃La(VO₄)₃:Eu³⁺ phosphors. Modulation of the emitting color from green to red can be realized by adjusting the Eu³⁺ doping concentration, which is assigned to an efficient energy transfer from VO₄³⁻ to Eu³⁺ ions. Notably, the optical thermometry of Ba₃La(VO₄)₃:Eu³⁺ was characterized based on the fluorescence intensity ratio of VO₄³⁻ and Eu³⁺ emissions in the 298–573 K range, with the maximum absolute and relative sensitivities of 0.0515 K⁻¹ and 1.77% K⁻¹ at 298 K. In addition, similar phenomena were observed in Sm³⁺ and Dy³⁺-doped Ba₃La(VO₄)₃ phosphors. These results verify a feasible strategy for varying the emission color and realizing optical thermometry in the single-component phosphors by adjusting the energy transfer between the host and the activator. It provides new possibilities for the design of multifunctional materials for white light-emitting diodes and non-contact thermometry.