Investigation of photoluminescence properties, Judd–Ofelt analysis, luminescence nanothermometry and optical heating behaviour of Er3+/Eu3+/Yb3+:NaZnPO4 nanophosphors

Abstract

Er³⁺/Eu³⁺/Yb³⁺:NaZnPO₄ nanophosphors synthesized using the co-precipitation technique are structurally and optically characterized. The effect of the Eu³⁺ ion concentration on the photoluminescence (PL) emission intensity and the energy transfer mechanisms implicated in the nanophosphors presented is discussed. The red to green intensity ratio, quantum yield and asymmetry ratio are calculated. The Eu–O ligand behaviour and spectral characteristics are explained in the light of the nephelauxetic ratio and the Judd–Ofelt parameters. A maximum sensitivity of ∼7.3 × 10⁻³ K⁻¹ at 503 K and the optical heating behaviour with the incorporation of Eu³⁺ ions in the Er³⁺–Yb³⁺:NaZnPO₄ nanophosphors are reported.