Eu^3+/2+ co-doping system induced by adjusting Al/Y ratio in Eu doped CaYAlO₄: preparation, bond energy, site preference and ⁵D₀–⁷F₄ transition intensity

Abstract

CaY1−xAl1+xO4:2%Eu (x = 0, 0.1, 0.2) phosphors have been synthesized via a solid-state reaction process.

Influence of Ga Substitution on the Local Structure and Luminescent Properties of Eu-Doped CaYAlO4 Phosphors

“…To resolve this, substituting Si 4+ for Al 3+ has been suggested to provide a larger space at the Ca/Y sites to accommodate Eu 2+ ions [20]. It has also been reported that changing the ratio of Y 3+ to Al 3+ leads to the activation of Eu 2+ emission [21], whose idea is based on the Eu 2+ emission hosted by CaAl 2 O 4 [22,23]. Such composition engineering, including chemical substitution, is a basic approach to designing the luminescence properties of phosphors via adjusting the local environment around luminescent centers; thus, it has been studied in a myriad of phosphors [24][25][26][27][28].…”

Governing the crystallographic sites for tuning Eu2+ emission in an apatite oxyfluoride host to be applied for superior white light emitting diodes

“…The parity-forbidden sharp 4f–4f transitions in the Eu 3+ -activated phosphor lead to a low colour rendering index (CRI), and the 4f–5d transitions in Eu 2+ cause an intensely broad band emission, which is more applicable for white-light-emitting applications. 27 The spectroscopic properties of Eu 3+ ions highly depend on the local environment. For instance, if the dopant enters the specific site under examination, then its emission behaviour depends on the symmetry of the site, which can be changed because of the slight alteration in the ligand field.…”

Multiple‐response anti‐counterfeiting realized in CaYAl3O7 host with the dual coexistence of Eu2+/Eu3+

“…Herein, the coexistence of Eu 2+ and Eu 3+ ions suggests a dual‐mode optical output, which would provide the possibility for multi‐dimensional anti‐counterfeiting application. In fact, the manipulation of the appearance of Eu 2+ and Eu 3+ ions in a single host matrix has been investigated in CaYAlO 4 , La 10 (SiO 4 ) 6 O 3 and Ca 8 La 2 (PO 4 ) 6 (SiO 4 )O 2 . It is believed that highly compress or highly symmetry structure compounds lead to difficulty in reduction of europium, even under reducing atmosphere for the coexistence of Eu 2+ and Eu 3+ .…”