Evolution of different defect clusters in Eu³⁺ doped KMgF₃ and Eu³⁺, Li⁺ co-doped KMgF₃ compounds and the immediate impact on the phosphor characteristics

Abstract

Different type of defect clusters were found to exist in Eu3+:KMgF3 and Li+, Eu3+:KMgF3 compounds, which can change the surrounding local structure of Eu3+ dopant ion. This resulted in different emission characteristics of Eu3+ ions, which can change the phosphor characteristics of the compounds.

Interplay between local distortion at lattice sites with optical and electrical properties of Eu3+-doped MNbO3 (M = Na and K) compounds

“…[21][22][23] Among the lanthanides, the Eu 3+ ion is widely used as a dopant ion to develop red-coloured phosphors. [24][25][26][27][28][29] A few works on the luminescence properties of Eu 3+ -doped NaNbO 3 and KNbO 3 matrices have also been reported separately. 30,31 Distortion at the lattice site in the perovskite class of materials plays a huge role in deciding the physical properties of such materials and is of great importance to understand how the doping of a luminescent ion, such as Eu 3+ ion, can influence the local distortion; in particular, concerning the first coordination shell.…”

Defect clustering in an Eu-doped NaMgF3 compound and its influence on luminescent properties

“…Analysing the number of lines for each transition in the emission spectrum and comparing it with the Tanner diagram72 indicates C 3v or C 4v symmetry. Previous work carried out with Eu 3+ -doped KMgF 3 suggested the same symmetry [28][29][30]. However, C 3v , C 4v , and C n are symmetry groups without inversion centres.…”

“…Another point that deserves to be highlighted is the substitutional defect and charge compensation created by inserting Eu 3+ into the host matrix. Reports for materials from the same family (Eu 3+ -doped KMgF 3 [28][29][30] and RbMgF 3 31 ) have diverged in relation to substitutional defects and charge compensation. The reports for Eudoped KMgF 3 have suggested a Na substitutional defect, [28][29][30] while one report for Eudoped RbMgF 3 suggested an Mg substitutional defect.…”

“…Reports for materials from the same family (Eu 3+ -doped KMgF 3 [28][29][30] and RbMgF 3 31 ) have diverged in relation to substitutional defects and charge compensation. The reports for Eudoped KMgF 3 have suggested a Na substitutional defect, [28][29][30] while one report for Eudoped RbMgF 3 suggested an Mg substitutional defect. 31 Our results for the Eu 3+ ion in NaMgF 3 show a Mg substitutional defect compensated by a Na vacancy in the calculations with defect clustering (see Fig.…”

“…Mechanisms of charge compensation are not yet established for Eu 3+ -and Eu 2+ -doped NaMgF 3 . Some reports have suggested different types of charge compensation in materials of the same family (KMgF 3 [28][29][30] and RbMgF 3 31 ) doped with different lanthanide ions. However, these discussions are based on ion sizes (doped and host), ignoring discussions about lattice solution energy.…”