Crystal Structure Induced Enhanced Afterglow Luminescence from Rare‐Earth Ion Doped Strontium Silicate Phosphors

Abstract

An orange-red (∼ 610 nm) emitting Sr 3 SiO 5 :Eu 2 + ,Zn 2 + ,Dy 3 + long afterglow phosphor was synthesized using high temperature (1100°C-1500°C) based solid-state reaction method under controlled reducing atmosphere. X-ray diffraction (XRD) study confirms the tetragonal lattice structure having space group P4/ncc. Scherrer's size plot and Williamson-Hall methods have been applied to study the particle size distribution and inherent strain, respectively, using crystallographic data obtained from XRD patterns. Electron microscopy images showed the surface morphology with an average crystallite size of 0.412 μm. Furthermore, detailed luminescence study was performed to observe photoluminescence (PL) and afterglow characteristics. An optimal PL emission peak was registered at ∼ 610 nm when the phosphor was excited by visible blue (∼ 465 nm) light, which is due to the transitions from 4f 6 5d 1 to 4f 7 energy levels of Eu 2 + ions. The enhanced afterglow property of > 20 minutes has been achieved for dark-adapted human eyes, which could be utilized for designing strategic markings and signage boards that could glow in dark.