Structure and light emission of scheelite-type <i>A</i>Ce(WO₄)₂ (<i>A</i> = Li, Na, or K)

Abstract

In this study, KCe(WO 4 ) 2 was synthesized by a solid-state reaction of K 2 CO 3 , CeO 2 , and WO 3 at 1273 K for 12 h. The Rietveld refinement of this sample confirmed the scheelite-type (tetragonal) structure for KCe(WO 4 ) 2 , with a I4 1 /a space group and lattice parameters a = 542.4 pm and c = 1207 pm. The lattice parameters for ACe(WO 4 ) 2 (A = Li, Na, or K) were in agreement with the ionic radii of the alkali metal ions, but the WO distance in KCe(WO 4 ) 2 was found to be shorter than those in the other compounds, indicative of the distortion of WO 4 2 , attributed to the larger ionic radius of K + . All of the synthesized ACe(WO 4 ) 2 materials exhibited fluorescence, with the relative emission intensity decreasing in the order of KCe(WO 4 ) 2 > NaCe(WO 4 ) 2 > LiCe(WO 4 ) 2 .

Average Structure, Local Structure, Photoluminescence, and NLO Properties of Scheelite Type NaCe(WO4)2

“…For instance, Dirany et al investigated the tunable morphologies of NaCe­(WO 4 ) 2 via an EDTA assisted method and showed variation in optical absorption properties with morphology . Nevertheless, use of additives such as surfactants or structure directing agents during synthesis was found to reduce fluorescence intensity in most of the luminescent materials. , Very recently Shimemura et al reported ACe­(WO 4 ) 2 where A = Li + , Na + , and K + by a conventional method and showed the effect of an alkali metal ion on emission properties. However, the spectral properties of the Ce 3+ ion in the Scheelite-like NaCe­(WO 4 ) 2 structure are not clear and the nonlinear optical properties have not been studied to date.…”

Synthesis, crystal structures and properties of the new compounds K7–x Ag1+x (XO4)4 (X = Mo, W)

“…A large number of double molybdates and tungstates of alkaline elements with di-or trivalent metals is an area of increasing interest because of the wide range of important physical properties and because of the potential applications of these compounds, such as promising optical materials (Maczka et al, 2012;Shimemura et al, 2017), effective phosphors (Benoît et al, 2011;Mo et al, 2012;Wang et al, 2009), laser materials (Balda et al, 2006;Yu et al, 2016;Loiko et al, 2016), as well as ferroelectrics (Isupov, 2005a,b) and solidstate electrolytes (Savina et al, 2013;Tsyrenova et al, 2016;Shukaev et al, 2016;Solodovnikov et al, 2017). Double molybdates and tungstates of two different alkali cations are also of special interest.…”

Hydrothermal synthesis of defect-induced pristine α-NaCe(WO4)2: a novel material for solid state lighting and gas sensing

“…), have emerged as promising materials due to their favourable physical and chemical properties, and high quantum yields etc. 4 In contrast to oxide-and fluoride-based luminescent materials, ALn(WO 4 ) 2 materials exhibit minimal photobleaching, and narrow emission bands etc., wherein their 4f-5d transitions and related optical properties, like Stokes shift, radiative and non-radiative lifetime etc. specifically depend on the crystalline field of the Ln 3+ species.…”

“…In this context, whilst several studies on β-ALn(WO 4 ) 2 have been conducted, relatively less work has been done to comprehend the various optoelectronic features of α-ALn(WO 4 ) 2 , specifically of α-NaCe(WO 4 ) 2 . To the best of our knowledge, some previous work has been conducted in this area, for instance, Shimemura et al analysed the optical emissions from ACe(WO 4 ) 2 where A = Na, Li, and K, 4 whereas Munirathnappa et al have only recently synthesized NaCe(WO 4 ) 2 via a template-free solvothermal approach, and they found a correlation between the distorted noncentrosymmetric structure and optical nonlinear second harmonic generation. 5 Dirany et al investigated the variation of optical absorption of NaCe(WO 4 ) 2 regarding relation to its morphology.…”