Synthesis and Optical Properties of Ho3+, Pr3+ Co-doped LaF3 Nanocrystals

Abstract

Abstract: Ho³⁺, Pr³⁺ co-doped LaF₃ nanocrystals have been prepared by hydrothermal method. The nanocrystals possess hexagonal structure with  space group with lattice parameters a = 7.17 ± 0.01 Å and c = 7.33 ± 0.01 Å. The room temperature absorption, photoluminescence (PL) and photoluminescence excitation (PLE) spectra of LaF₃:Ho³⁺, Pr³⁺ were investigated in detail. It was discovered that the PL and PLE of Ho³⁺ and Pr³⁺ ions resulted from the optical intra-configurational f-f transitions. The PL spectra are attributed to the transitions ⁵F₃, ⁵S₂ +⁵F₄ and ⁵F₅ → ⁵I₈ in Ho³⁺ ion and the transitions ³P₀→³H₅, ¹D₂→³H₄, ³P₀→³H₆, ³F₂ and ³F₄ in Pr³⁺ ion. The optical transitions ⁵I₈→ ⁵F₅, ⁵F₄, ⁵F₃, ³K₈, ⁵F₁, ⁵G₅, ³K₇ and ³H₆ in Ho³⁺ ion and the optical transitions ³H₄ → ³P₂ , ³P₁, ³P₀ and ¹D₂ in Pr³⁺ ion have been clearly observed not only in the PLE spectra, but also in the absorption spectra.

Keywords: LaF₃:Ho³⁺, Pr³⁺ nanocrystals, rare-earth, hydrothermal, absorption, photoluminescence.