Synthesis, Luminescence, and Energy Transfer Properties of YPO₄:Gd³⁺, Eu³⁺ and YP₃O₉:Sm³⁺, Eu³⁺ Phosphors

Abstract

This work is concerned with the search for new luminescent materials emitting in the orange-red color. We have synthesized YPO₄ doped with Gd³⁺0.25% and/or Eu³⁺0.50% by hydrothermal method and YP₃O₉ doped with Sm³⁺0.25% and/or Eu³⁺0.50% by ultraphosphate decomposition reaction. Phase purity was checked by FTIR and XRD. Excitation and emission spectra and fluorescence decay measurements were recorded at room temperature (RT). Emission spectra allow to determine the site symmetry of rare earth (RE³⁺) in the crystallographic structure of matrices. Weak Eu³⁺ emission is detected from YPO₄:Gd³⁺, Eu³⁺ under excitation at 273 nm. Sm³⁺ levels were detected in excitation spectrum of YP₃O₉:Sm³⁺, Eu³⁺ monitoring Eu³⁺ principal emission at 618 nm. Excited states lifetimes of Gd³⁺ and Sm³⁺ sensitizers (S) decrease from mono-doped to co-doped matrices indicating an Energy transfers (ET) from S to Eu³⁺ with a rate higher than 19%.