Template-free hydrothermal synthesis and luminescence properties of NaGd(WO4)2:Eu3+ red phosphors with controlled morphology

Na(Gd,RE)(WO4)2 double tungstates (RE=Eu/Yb-Er): crystallization from a novel layered hydroxide precursor and favorable luminescence for optical thermometry

“…Milli-Q filtered water (resistivity >18 MΩ•cm) was used throughout the experiments. According to previously references 5% doping already made the host show good photoluminescence properties [18,19] O precursors (Ln-241) typically involves hydrothermal reaction of an aqueous solution (60 mL) containing 6 mmol of Ln nitrates and 6 mmol of (NH 4 ) 2 SO 4 under 100°C and pH = 7 for 24 h, and the details of which can be found elsewhere [24]. For phase conversion synthesis of double tungstates, the Ln-241 precursor was dispersed in 60 ml of Na 2 (WO) 4 solution (WO 4 2-:Ln 3+ molar ratio = 2.5) by 30 min of magnetic stirring, followed by hydrothermal reaction in a Teflon-lined stainless steel autoclave at a predetermined temperature (100-200°C) for 24 h. After natural cooling, the hydrothermal product was collected via centrifugation, washed with water three times and absolute ethanol once, and then dried in air at 70°C for 24 h.…”

“…What's more, the layered structure of NaGd(WO 4 ) 2 (Figure S1) beneficially delays the concentration quenching process of activator as most rare earth are well isolated by [WO] 4 tetrahedron and have large RE-RE distance of 5.2483 Å (Figure S1 (a)). Although some rare earth are adjacent and have RE-RE distance of 3.8726 Å (Figure S1 (b)) the optimal concentration of Eu in NaGd(WO 4 ) 2 are reported as high as 8-12% and desirable luminescence properties can also be achieved at lower doping level [16][17][18][19]. Very recently Na(Ln,RE)(WO 4 ) 2 as optical thermometer has been reported and comparably higher S A and S R values have indeed been achieved from the systems [13,14,20,21].…”

Research on the progress of Ce3+,Tb3+ co-activated phosphate luminescent materials prepared by hydrothermal method

“…At present, most LAPs are prepared by high temperature solid phase method, which has the disadvantage of being unable to control the particle morphology of materials. The samples prepared are usually severely agglomerated and cannot be uniformly coated, which restricts their further expansion and application [10,11]. The apparent structure of materials, such as morphology and size, has a significant impact on the luminescent properties of materials.…”

Synthesis, functionalization and properties of uniform europium-doped sodium lanthanum tungstate and molybdate (NaLa(XO4)2, X = Mo,W) probes for luminescent and X-ray computed tomography bioimaging

“…A possible reason for that might be the unavailability of synthesis methods to produce this material with the needed characteristics mentioned above. Most previous reported methods for the synthesis of uniform NaLa(WO4)2 particles resulted in micron sized entities, [19][20][21][22][23][24][25] which do not meet the size criteria. Only Wang et al, recently reported a procedure, which produced Dy and Sm doped NaLa(WO4)2 nanocubes based on a solvothermal reaction using oleic acid as dispersing and capping agent [26].…”