The Luminescence Properties of the Interstitial Eu²⁺ in SrB₂O₄ for UV Light‐Emitting Diode

Abstract

SrB2O4:Eu2+ is prepared by the high‐temperature solid‐phase method. The structure is characterized by X‐ray diffraction, and the luminescence properties are analyzed using fluorescence spectroscopy and decay curves. SrB2O4:Eu2+ has strong absorption in the UV region and two broadband emissions in the 350–550 nm, located at 374 and 458 nm. The broadband emission around 374 nm belongs to Eu2+ emission at the Sr lattice position, and the emission around 458 nm belongs to interstitial Eu2+ ions. At low concentrations, Eu2+ replaces the position of Sr2+ first, and the emission peak of 374 nm is stronger than that of 458 nm in the emission spectrum. The luminescence at 458 nm enhances significantly as the concentration of Eu2+ ions increases. The fluorescence lifetime confirms the presence of two luminescent centers, the EuSr and the interstitial Eu2+ ions. The temperature dependence luminescence of SrB2O4:Eu2+ is explored, and the activation energy is calculated to be ΔEa = 0.3622 eV. The Commission Internationale de l'Éclairage (CIE) chromaticity coordinates of SrB2O4:Eu2+ are in the blue area. The results indicate that the interstitial Eu2+ benefits the color‐rendering index when SrB2O4:Eu2+ is used as a blue phosphor in UV light‐emitting diode (LED).

Tunable emission and thermal sensitivity via energy transfer from Bi3+ to Eu3+ in BaY2Al2Ga2GeO12

“…Because the 1 P 1 level is less stable and the electrons jump to the lower energy 3 P 1 level through the nonradiative transition, the primary emission of Bi 3+ ion is attributed to the 3 P 1 → 1 S 0 electron transition. Since the emission of Bi 3+ overlaps with the excitation of Eu 3+ , part of the energy is reabsorbed by 5 D or 5 L of Eu 3+ . Then, the electron on higher levels 5 L 7 , 5 L 6 , and 5 D 2 jumps to lower energy 5 D 0 through nonradioactive relaxation (NR).…”

“…Rare earth ions, such as Ce 3+ , Tb 3+ , Eu 2+ , Eu 3+ and Sm 3+ , and transition metal ions, such as Mn 2+ , Mn 4+ and Cr 3+ , are often used as sensitizers. 2–5 The garnet structure has excellent physical and chemical properties, containing three different lattice environments including tetrahedron, octahedron, and dodecahedron for doping ions. 6 Therefore, it is a good choice to design and realize single-phase white phosphors based on the garnet structure.…”