Structure and Luminescence in Long Persistence Eu, Dy, and B Codoped Strontium Aluminate Phosphors: The Boron Effect

Abstract

Long persistence phosphors are promising materials for energy‐saving applications, due to their ability to temporarily store and release light. While boron is known to dramatically extend the afterglow persistence to longer than 8 h in strontium aluminates, previous attempts to understand the role of boron neglected any nanoscale‐related effects and have been inconclusive. Herein, nanoscale‐resolved cathodoluminescence mapping is correlated with selected area electron diffraction and with energy dispersive x‐ray spectroscopy analysis using a 2 Å‐diameter probe. The salient aspect of this unique approach is that one can not only determine the elemental distribution in the phosphor microstructure, but more importantly, one can discriminate between the distributions of different divalent and trivalent luminescing ions. We demonstrate that the extremely long afterglow is due to the boron dopant via two key roles: (1) facilitating dominance of the long persistence phase during the microstructural evolution and (2) promoting more uniform distribution of the optically active, Eu2+ ion in the Sr2+ cation sublattice.

The boron effect on low temperature luminescence of SrAl2O4:Eu, Dy

“…Therefore the afterglow intensity dependence of time was measured in room temperature. Evaluated by human eye, the afterglow was not present after a minute after the termination of excitation in the samples with boron concentrations 0% and 1%, whereas the samples with boron concentrations 5, 7, 10 and 15% were glowing for more than 10 h after the termination of excitation, as it was expected from the literature [12,14]. Concentrations of boron in range of 5%-15% lead to similar afterglow times and decay profiles.…”

“…Moreover, close afterglow intensity for samples containing boron concentration in raw material within range of 7%-15% is in agreement with XPS data in Table 2. As many articles have stated before [12,14], boron addition can prolong the intensity of the afterglow. Therefore the afterglow intensity dependence of time was measured in room temperature.…”

Synthesis, luminescence and persistent luminescence of europium-doped strontium aluminates

“…Without boron oxide, SA is the main product at the reaction temperature of 1373 K. With more than 30% B2O3, SA6 is obtained. Akmehmet et al [70] investigated the effects of boron on the microstructure and luminescence of S4A7:Eu 2+ ,Dy 3+ by nanoscale-resolved cathodoluminescence mapping technique. They applied the same sol-gel method for preparation of the precursor material in the presence and absence of B2O3 in the reaction mixture.…”

Absorption and Remission Characterization of Pure, Dielectric (Nano-)Powders Using Diffuse Reflectance Spectroscopy: An End-To-End Instruction

“…During a wavelength-sweep, luminescent materials may emit signals separated by an octave or more to the momentarily investigated wavelength. If the same setup is used on both excitation and detection side, such potentially transmitted higher order diffracted wavelengths entail a similar spectral filtering, especially if luminescence lifetimes become comparable to scan speeds, in particular when samples are cooled [97][98][99][100][101][102].…”