Influence of annealing conditions on the structure and luminescence properties of KGd1-: XEux(MoO4)2 (0 ≤ x ≤ 1)

Vladimir A. Morozov, Svetlana M. Posokhova, Dina V. Deyneko, Aleksandra A. Savina, Anatolii V. Morozov, Oleg A. Tyablikov, Boris S. Redkin, Dmitry A. Spassky, Joke Hadermann, Bogdan I. Lazoryak

Результат исследований: Вклад в журналСтатьярецензирование

5 Цитирования (Scopus)


This study describes the influence of annealing temperature on the structure and luminescence properties of KGd1-xEux(MoO4)2 (0 ≤ x ≤ 1). Compounds with the general formula (A′, A′′)n[(W, Mo)O4]m are investigated as luminescent materials for photonic applications such as phosphor-converted LEDs (light-emitting diodes). Herein, the KGd0.8Eu0.2(MoO4)2 light-rose crystal was grown by the Czochralski technique. Moreover, three polymorphs of KGd1-xEux(MoO4)2 were present in the 923-1223 K range of annealing temperatures under ambient pressure: a triclinic α-phase, a disproportionately modulated monoclinic β-phase and an orthorhombic γ-phase with a KY(MoO4)2-type structure. The different behaviors of KGd(MoO4)2 and KEu(MoO4)2 were revealed by DSC studies. The number and the character of phase transitions for KGd1-xEux(MoO4)2 depended on the elemental composition. The formation of a continuous range of solid solutions with the triclinic α-KEu(MoO4)2-type structure and ordering of K+ and Eu3+/Gd3+ cations were observed only for α-KGd1-xEux(MoO4)2 (0 ≤ x ≤ 1) prepared at 923 K. The structures of γ-KGd1-xEux(MoO4)2 (x = 0 and 0.2) were studied using electron diffraction and refined using the powder X-ray diffraction data. The luminescence properties of KGd1-xEux(MoO4)2 prepared at different annealing temperatures were studied and related to their different structures. The maxima of the 5D07F2 integral emission intensities were found under excitation at λex = 300 nm and λex = 395 nm for triclinic scheelite-type α-KGd0.6Eu0.4(MoO4)2 and monoclinic scheelite-type β-KGd0.4Eu0.6(MoO4)2 prepared at 1173 K, respectively. The latter shows the brightest red light emission among the KGd1-xEux(MoO4)2 phosphors. The maximum and integral emission intensity of β-KGd0.4Eu0.6(MoO4)2 in the 5D07F2 transition region is ∼20% higher than that of the commercially used red phosphor Gd2O2S:Eu3+. Thus, β-KGd0.4Eu0.6(MoO4)2 is very attractive for application as a near-UV convertible red-emitting phosphor for LEDs.

Язык оригиналаАнглийский
Страницы (с-по)6460-6471
Число страниц12
Номер выпуска42
СостояниеОпубликовано - 2019


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