Structural Characterization and Luminescent Properties of a Red Phosphor Series: Y_2−xEu_x(MoO₄)₃ (x=0.4–2.0)

Abstract

A series of rare earth molybdates, Y2−xEux(MoO4)3 for x=0.4, 0.8, 1.2, 1.6 and 2.0 were prepared by solid‐state method and their crystal structures, photo luminescent characteristics were investigated. The powders are mainly studied for their red light emission efficiency under near UV excitation. The crystal structures of the powders were found to depend on annealing temperature and the yttrium concentration. Mixtures of monoclinic (C2/c) and orthorhombic (Pba2, Pbna) structures were formed in varying proportions depending on the value of x and annealing temperatures (700°–800°C). The luminescence behavior depended on the resultant composition of the crystal phase and the Eu3+ concentration. The excitation spectra showed the characteristic and broad O→Mo charge transfer (CT) band of the MoO4 tetrahedra and the sharp intra‐configurational 4f–4f transitions of Eu3+ in the host lattice. The integrated emission ratio (5D0→7F2/5D0→7F1) of Eu3+ depends on the annealing temperature and reveals that the local site symmetry of Eu3+ ions decreases with increasing concentration of Eu3+. The emission spectra obtained by exciting at 396 nm, gave highest red emission intensity for Y0.4Eu1.6(MoO4)3 annealed at 700°C/6 h among this series of samples.

Dual-Mode Luminescence with Broad Near UV and Blue Excitation Band from Sr2CaMoO6:Sm3+Phosphor for White LEDs

“…15 At present, many attentions have been attracted to rare earth ions activated alkaline earth molybdate compounds acting as phosphors for LEDs thanks to their efficient energy transfer from the broad charge transfer band in near UV region, as well as chemical and thermal stability. [16][17][18][19] It has been found that the coordination number groups make them suitable for near UV pumped LEDs. They were usually used as red phosphors owing to the high energy transfer efficiency in the MoO 6 -Eu 3+ systems.…”

Synthesis of KMgCl3 nanomaterial and luminescence of Ce3+/Dy3+/Eu3+ by different routes

“…Trivalent Eu ion, as one of the promising species that provide optical emission in red color regions, has been doped in various compounds. Trivalent Eu ion has been expected as one of the promising species that provide optical devices in red color regions and many investigations have been conducted in various compounds [11][12][13]. Trivalent Eu emission is very useful for studying the nature of metal coordination in various systems owing to its non-degenerate emitting 5 D 0 state.…”

Synthesis and luminescent properties of novel red-emitting M7Sn(PO4)6:Eu3+(M= Sr,Ba) phosphors

“…In recent years, extensive research has been carried out on rare-earth-doped phosphors because of several important superior properties, such as luminescent characteristics,stability in vacuum, and corrosion-free gas emission under electron bombardment compared with traditional cathode ray tube used in current field emission displays [7,8]. Trivalent Eu ion, as one of the promising species that provide optical emission in red colour regions, has been doped in various compounds [9][10][11]. However, to the best of our knowledge, there is no report on the research of M 7 Sn(PO 4 ) 6 (M = Sr, Ba) phosphor activated by rare earth or transition metal.…”