Structure and photoluminescent properties of green‐emitting terbium‐doped GdV_1−xP_xO₄ phosphor prepared by solution combustion method

Abstract

Terbium-doped gadolinium orthovanadate (GdVO4 :Tb(3+) ), orthophosphate monohydrate (GdPO4 ·H2 O:Tb(3+) ) and orthovanadate-phosphate (GdV,PO4 :Tb(3+) ) powder phosphors were synthesized using a solution combustion method. X-Ray diffraction analysis confirmed the formation of crystalline GdVO4 , GdPO4 ·H2 O and GdV,PO4 . Scanning electron microscopy images showed that the powder was composed of an agglomeration of particles of different shapes, ranging from spherical to oval to wire-like structures. The chemical elements present were confirmed by energy dispersive spectroscopy, and the stretching mode frequencies were determined by Fourier transform infrared spectroscopy. UV-visible spectroscopy spectra showed a strong absorption band with a maximum at 200 nm assigned to the absorption of VO4 (3-) and minor excitation bands assigned to f → f transitions of Tb(3+) . Four characteristic emission peaks were observed at 491, 546, 588 and 623 nm, and are attributed to (5) D4 → (7) Fj (j = 6, 5, 4 and 3). The photoluminescent prominent green emission peak ((5) D4 → (7) F5 ) was centred at 546 nm. The structure and possible mechanism of light emission from GdV1-x Px O4 :% Tb(3+) are discussed. Copyright © 2016 John Wiley & Sons, Ltd.

Effect of calcination temperature on phase evolution and photoluminescent properties of GdPO4:Eu3+ nanoparticle phosphors synthesized by combustion method

“…[6] As-prepared samples after hydrothermal process at 180 o C or 200 o C are also presented hexagonal phase, [8,9] then the phase will completely transform from hexagonal to monoclinic phase when annealed at 700 o C. [8,9] While Lanchun Zou reported that, it still was hexagonal GdPO 4 .H 2 O phase when sample was canlcined at 700 o C and pure monoclinic GdPO 4 phase could acquired when the reaction temperature was up to 800 and 900 o C. [6] By combustion synthesis, broad diffraction peaks of monoclinic phase were obtained in as-prepared GdPO 4 :Ho 3+ ,Yb 3+ samples annealed at 250 o C, and sharp diffraction peaks of monoclinic phase were receilved; [10] while for the case of GdPO 4 :Tb 3+ samples, hexagonal GdPO 4 .H 2 O phase (JCPDS No. 39-0232) was observed till annealed at 600±10 o C. [11] The SEM image of GdPO 4 :Eu 3+ nanopowders annealed at 900 °C is shown in Fig. 2.…”

“…Several methods have been reported for the synthesis of rare-earth doped GdPO 4 crystals, such as co-precipitation, [5] hydrothermal, [6][7][8][9] sol-gel. [10] As far as we know, few studies have been published on synthesis of rare-earth doped GdPO 4 nanocrystals, such as GdPO 4 :Ho 3+ ,Yb 3+ [10] and GdPO 4 :Tb 3+ , [11] and no work has been reported on the synthesis of GdPO 4 :Eu 3+ nanocrystals by combustion method. We herein present a straightforward combustion method to prepare Eu 3+ doped GdPO 4 .…”

The Influence of Defects on the Luminescence of Trivalent Terbium in Nanocrystalline Yttrium Orthovanadate

“…Luminescent rare-earth (RE) oxides have been extensively explored both in terms of theoretical detailing of 4f–4f transitions and for their unique applicability in lighting, visualization, nonlinear optics, and biolabeling technologies. − RE vanadates (REVO 4 ) are chemically stable and remarkably versatile hosts for lanthanoid (Ln) optical centers with downshift and upconversion emissions, which enable emerging applications in nanothermometry, sensing, and catalysis. − While Eu 3+ -doped YVO 4 is an ubiquitous UV-excited red phosphor, ,,, the inactivity of Tb 3+ -doped YVO 4 is an intriguing aspect in the chemistry and spectroscopy of vanadate-based luminescent materials. ,, During the search for efficient lamp phosphors in the late 1960s, many groups reported the complete absence of Tb 3+ luminescence in YVO 4 as well as the strong quenching of other Ln 3+ emissions induced by Tb 3+ -codoping. − Even though some groups studied Tb 3+ emissions in lanthanum (LaVO 4 ) − or gadolinium (GdVO 4 ) − vanadates, papers mentioning any luminescence in tetragonal YVO 4 :Tb 3+ are scarce, ,,, and no spectra or detailed characterization have been reported. The description of the Tb 3+ luminescence in AXO 4 zircon-type solids has been mainly performed for yttrium phosphates (YPO 4 ), phosphovanadates (YP 1– x V x O 4 ), and arsenovanadates (YAs 1– x V x O 4 ), which are isostructural to YVO 4 . ,− …”