Photoluminescence features of new Eu³⁺ -doped Gd₄Mo₇O₂₇ phosphors synthesized using glass crystallization technique

Abstract

New Eu 3+-doped Gd 4 Mo 7 O 27 crystals (the molar ratio of Gd 2 O 3 /MoO 3 = 1/3.5) with a monoclinic structure C2/c (an inversion symmetry) were synthesized through the crystallization of xEu 2 O 3-(18.89-x)Gd 2 O 3-66.11MoO 3-15B 2 O 3-1Al 2 O 3 glasses (x = 0.0472 and 1.889) and photoluminescence (PL) emissions of Eu 3+ ions were measured for the first time. The crystallized glass with no Eu 2 O 3 addition (x = 0) showed a blue color under the irradiation of ultraviolet light with a wavelength of λ = 254 nm, the emitting color of the crystallized glass with x = 0.0472 was pink, and that of the crystallized glass with x = 1.889 was orange. The charge transfer (CT) of O 2-→Mo 6+ providing broad peaks centered at around 325 nm was observed in the crystallized glasses. The peak intensity at 591 nm for the 5 D 0 → 7 F 1 transition of Eu 3+ ions in the crystallized glasses with x = 0.0472 and 1.889 was very close to that at 615 nm for the 5 D 0 → 7 F 2 transition for the excitation of λ ex = 394.5 nm. We propose potential of Gd 4 Mo 7 O 27 as a new host crystal for rare-earth-doped phosphors.

Stress‐induced crystal axis spiral rotation in multiferroic β'‐Gd2(MoO4)3 observed only in glass crystallization

“…The Gd 4 Mo 7 O 27 crystalline phase has not been reported in the phase diagram for the binary Gd 2 O 3 -MoO 3 system. 73,74 The glass-ceramics consisting of Gd 4 Mo 7 O 27 crystals have been proposed for the first time by Kotaka et al 72 75 As an example, the PL emission spectra under the excitation of λ ex = 394.5 nm for the crystallized samples with Eu 2 O 3 = 1.889 mol% are shown in Figure 21. The PL emissions due to the 4f → 4f transitions of Eu 3+ ions in Eu 3+ -doped Gd 4 Mo 7 O 27 crystals are clearly observed in the crystallized (590 and 630°C) samples.…”

“…It has been proposed that Gd 4 Mo 7 O 27 has a high potential as a new host crystal for rare-earth doped phosphors. 75…”

“…The glass‐ceramics consisting of Gd 4 Mo 7 O 27 crystals have been proposed for the first time by Kotaka et al 72 It is noted that the structure of Gd 4 Mo 7 O 27 crystal consists of MoO 4 , MoO 5 , GdO 7 , and GdO 8 units, 73 although β'‐Gd 2 (MoO 4 ) 3 crystal includes only MoO 4 and GdO 7 units. New Eu 3+ ‐doped Gd 4 Mo 7 O 27 crystals with a monoclinic structure C 2/ c (an inversion symmetry) were synthesized through the crystallization of xEu 2 O 3 ‐(18.89‐x)Gd 2 O 3 ‐66.11MoO 3 ‐15B 2 O 3 ‐1Al 2 O 3 glasses ( x = 0.0472 and 1.889) and PL emissions of Eu 3+ ions were measured for the first time by Kotaka et al 75 As an example, the PL emission spectra under the excitation of λ ex = 394.5 nm for the crystallized samples with Eu 2 O 3 = 1.889 mol% are shown in Figure 21. The PL emissions due to the 4 f → 4 f transitions of Eu 3+ ions in Eu 3+ ‐doped Gd 4 Mo 7 O 27 crystals are clearly observed in the crystallized (590 and 630°C) samples.…”

“…It is noted that the peak intensity of the 5 D 0 → 7 F 1 transition is very close to that of the 5 D 0 → 7 F 2 transition for the excitation of λ ex = 394.5 nm. It has been proposed that Gd 4 Mo 7 O 27 has a high potential as a new host crystal for rare‐earth doped phosphors 75 …”

“…PL emission spectra under the excitation of λ ex = 394.5 nm for Eu 3+ ‐doped Gd 4 Mo 7 O 27 crystals obtained in the glass crystallization 75 [Color figure can be viewed at wileyonlinelibrary.com]…”