Multicolor-tunable up-conversion emissions of Yb3+,Er3+/Ho3+ co-doped Ba3Lu2Zn5O11: crystal structure, luminescence and energy transfer properties

Abstract

Yb³⁺–Er³⁺ and Yb³⁺–Ho³⁺ co-doped Ba₃Lu₂Zn₅O₁₁ phosphors were successfully obtained. The structure of the as-synthesized phosphor was determined by Rietveld refinement. The up-conversion (UC) spectra of Ba₃Lu₂Zn₅O₁₁:Yb³⁺,Er³⁺ exhibits two prominent emission bands centered at 560 and 663 nm, which originate from the ²H_11/2/⁴S_3/2 → ⁴I_15/2 and ⁴F_9/2 → ⁴I_15/2 transitions of Er³⁺, respectively. Ba₃Lu₂Zn₅O₁₁:Yb³⁺,Ho³⁺ revealed a bright green emission at around 553 nm and negligible red emission peaking at 660 nm, which were assigned to the ⁵F₄/⁵S₂ → ⁵I₈ and ⁵F₅ → ⁵I₈ transitions of Ho³⁺, respectively. The up-conversion luminescence of the samples was studied as a function of the concentration of the dopants. The origin of the UC mechanism is discussed in detail by analyzing energy-level diagrams, the dependence of the UC emission intensity on pump power, and the lifetimes. The results indicate that the Ba₃Lu₂Zn₅O₁₁:Yb³⁺,Er³⁺/Ho³⁺ phosphors are excellent up-conversion emitters and have potential applications in display and illumination technologies.