Synthesis and luminescence characteristics of yttrium, aluminum and lanthanum borates doped with europium ions (Eu 3+)

Abstract

Inorganic materials doped with rare earth (RE) ions are an object of intense research due to their optical and electrical properties. These materials have the potential for various applications, such as solid-state lasers, active planar waveguides, optical fiber amplifiers, light-emitting diodes (LEDs), displays, ink fillers, security features, etc. RE trivalent ions can emit light from the ultraviolet (UV) to the near-infrared (NIR) regions due to electronic transitions of the 4f-5d levels. Yttrium borate doped with europium ions was prepared by solid-state synthesis in a muffle furnace at 900oC for 4 hours, while lanthanum and aluminum borates doped with europium ions were prepared at 1000oC for 6 hours again in a muffle furnace. The resulting materials are fine white powders. Among the rare earth ions, europium is one of the most commonly used activators because the ions of Eu3+ and Eu2+ can be used as emission sites in the host lattices. Eu3+ ions can produce effective sharp emission peaks in different matrix compositions. Photoluminescence analysis of the samples was performed, based on which the luminescence intensity of the Eu3+ ion was determined through a comparative characteristic. YBO3:Eu3+ phosphor is optically active and chemically stable. It is characterized by a strong orange-red emission at ≈ 591 nm, ≈ 612 and ≈ 696 nm due to the 5D0→7F1 and 5D0→7F2 electronic transitions, respectively. Red emission is also observed for LaBO3:Eu3+ at ≈ 592 and ≈ 615 nm, characterizing the 5D0→7F1 and 5D0→7Fj (j=0, 1, 2, 3, 4) transitions. While aluminum borate doped with europium ion shows intense emission at ≈ 612 nm, making this material suitable for lighting devices. The technique of Fourier transform infrared spectroscopy (FTIR) was used to study the structure of the obtained materials.