Emission Quenching and First Evidence of Tb³⁺-to-As⁵⁺ Charge Transfer in Terbium(III) Ion-Doped YV_xAs_1–xO₄ Solid-State Solution

Abstract

The paper discusses the origin of emission quenching and the formation of metal-to-metal charge-transfer states in yttrium orthovanadate-arsenates doped with Tb3+ ions. For that purpose, a series of highly crystalline yttrium orthovanadate-arsenate nanoparticles (type YV x As1–x O4, where x = 2–65 mol %) doped with Tb3+ ions were prepared using the co-precipitation method. The structural and morphological properties of the particles were studied by means of X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) techniques. The photoluminescence spectral and dynamical properties of YV x As1–x O4 doped with 1 mol % Tb3+ ions were investigated in detail. It was found that the emission quenching is related to changes in the band gap and Tb3+-to-V5+ metal-to-metal charge transfer. Further, the Tb3+-to-As5+ metal-to-metal charge transfer was identified and rationalized based on different models.

Tunable luminescence thermal stability in YVxAs1−xO4:Eu3+ through the introduction of As5+ ions for remote temperature sensing applications

“…This is due to differences in the ionic radii of V 5+ and As 5+ . Previous research 15 investigated the emission quenching mechanisms of terbium ions (Tb 3+ ) in the yttrium orthovanadate-arsenate matrix. Those studies reveal that high concentration of (AsO 4 ) 3− in YV x As 1− x O 4 extends the lifetime of the 5 D 4 excited state of Tb 3+ , thus improving luminescent properties of the phosphor.…”

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 . ,− …”