Four-Dimensional Incommensurate Modulation and Luminescent Properties of Host Material Na₃La(PO₄)₂

Abstract

A series of orthophosphates NaLn(PO) (Ln = lanthanoids) have for a long time been known as good luminescent materials, yet their crystal structures have not been studied in full detail. In this work, compound NaLa(PO) was prepared using molten salt (flux) method and for the first time was structurally determined on X-ray single-crystal diffraction data. Interestingly, it crystallizes in the four-dimensional incommensurately modulated structure with orthorhombic superspace group Pca2(0β0)000 and modulation wave vector q = 0.387b*. Furthermore, to evaluate the potentiality of NaLa(PO) to be used as a luminescent host material, 5 mol % Eu, Tb, and Dy doped phosphors were prepared, respectively. The excitation spectra, emission spectra, decay time, quantum efficiency, and the color purity of prepared phosphors, NaLaEu(PO), NaLaTb(PO), and NaLaDy(PO), were studied.

Interplay between organic cations and inorganic framework and incommensurability in hybrid lead-halide perovskite CH3NH3PbBr3

“…[26,27,31] Mechanistic elucidation of incommensurate structures offer insight on a wide variety of research frontiers, ranging from fundamental understanding of exotic electronic and spin structures and properties, [32,33] to practical engineering of optical applications. [34] Incommensurability is always associated with the concept of frustration, namely a structural compromise that results from two incompatible interactions competing with each other. [35] In our low frequency Raman scattering observations, incommensurate phases exist in the hybrid perovskite CH 3 NH 3 PbBr 3 , but is absent in the inorganic perovskite CsPbBr 3 .…”

Broadband excited Na3Tb(PO4)2:Ce3+/Eu2+ green/yellow‐emitting phosphors with high color purity for LED‐based application

“…26 The refinement results demonstrate that the crystal structure of NTPO compound is similar to Na 3 Gd(PO 4 ) 2 but different from Na 3 La(PO 4 ) 2 featured superspace group Pca2 1 . 23,31 Raman spectroscopy technique is a useful and quick way to differentiate phosphate phases and compounds with sufficient sensitivity. Therefore, Raman spectra was decided to further identify the structure of Ce 3+ and Eu 2+ doping, as shown in Fig.…”

“…Rare-earth orthophosphates with the general formula Na 3 RE(PO 4 ) 2 are good hosts for RE ions luminescence due to the advantages of excellent chemical stability, low synthesized temperature, broad band gap and high luminescence efficiency, which have been extensively studied for diverse RE ions doping, such as blue-red dual-emitting Na 3 La(PO 4 ) 2 /LaPO 4 :Eu phosphor with high thermal stability, 21 Accepted Article orange/green/yellow-emitting Na 3 La(PO 4 ) 2 :Eu 3+ /Tb 3+ /Dy 3+ phosphor 22,23 and highly efficient red-emitting Na 3 Eu(PO 4 ) 2 phosphor. 24 The general crystal structure of Na 3 RE(PO 4 ) 2 is isomorphic with Na 3 La(VO 4 ) 2type structure (orthorhombic phase with space group Pbc21).…”

Cs2Zn5(PO4)4 and Cs3La(PO4)2: Two Cs‐Containing Phosphates with Three‐Dimensional Frameworks

“…Moreover, lanthanide (Ln)‐doped M 3 RE(PO 4 ) 2 are of great interest on account of their scintillation and luminescence properties . For example, Na 3 La(PO 4 ) 2 is a promising host material and Na 3 La(PO 4 ) 2 : 0.05Ln (Ln = Eu 3+ , Tb 3+ and Dy 3+ ) show the typical characteristic emission of activators; Eu 3+ ‐doped K 3 Y(PO 4 ) 2 exhibits an intense reddish orange emission under near UV light excitation; Ce 3+ ‐activated K 3 Lu(PO 4 ) 2 exhibits promising scintillation property with high light yields and relatively fast decay time …”