From Framework to Layers Driven by Pressure – The Monophyllo‐Oxonitridophosphate β‐MgSrP₃N₅O₂and Comparison to its α‐Polymorph

Abstract

Oxonitridophosphates exhibit the potential for broad structural diversity, making them promising hostcompounds in phosphor-converted light-emitting diode applications. The novel monophyllo-oxonitridophosphate β-MgSrP 3 N 5 O 2 was obtained by using the high-pressure multianvil technique. The crystal structure was solved and refined based on single-crystal X-ray diffraction data and confirmed by powder X-ray diffraction. β-MgSrP 3 N 5 O 2 crystallizes in the orthorhombic space group Cmme (no. 67, a = 8.8109( 6), b = 12.8096(6), c = 4.9065(3) Å, Z = 4) and has a structure related to that of Ba 2 CuSi 2 O 7 . DFT calculations were performed to investigate the phase transition from αto β-MgSrP 3 N 5 O 2 and to confirm the latter as the corresponding high-pressure polymorph. Furthermore, the luminescence properties of Eu 2 + doped samples of both polymorphs were investigated and discussed, showing blue and cyan emission, respectively (α-MgSrP 3 N 5 O 2 ; λ max = 438 nm, fwhm = 46 nm/2396 cm À 1 ; β-MgSrP 3 N 5 O 2 ; λ max = 502 nm, fwhm = 42 nm/1670 cm À 1 ).

(Dis)Order and Luminescence in Silicon-Rich (Si,P)–N Network Sr5Si7P2N16:Eu2+

“…We synthesized semicrystalline P 3 N 5 by reacting P 4 S 10 in a steady flow of ammonia at 850 °C, as described in the literature. , Sr­(N 3 ) 2 was prepared from SrCO 3 with aqueous HN 3 in a cation exchange reaction, as reported by Suhrmann et al and again by Pritzl et al , Amorphous Si 3 N 4 (UBE, SNA-00) was commercially available. For doping, we used europium­(III) nitride that we synthesized from Eu metal (smart-elements, 99.99%) and dried N 2 gas in a radiofrequency furnace (TIG 10/100; Hüttinger Elektronik Freiburg, Germany) at 1000 °C for 2 h.…”

Super-Tunable LaSi3N5 Structure Type: Insights into the Structure and Luminescence of SrSi2PN5:Eu2+

“…Sr­(N 3 ) 2 was obtained from the reaction of aqueous HN 3 with SrCO 3 , as recently described by Pritzl et al , Semicrystalline α-P 3 N 5 was synthesized from P 4 S 10 via ammonolysis as described in the literature . EuN was produced from elemental Eu (smart elements, 99.99%) in a tungsten crucible, which was heated under a nitrogen atmosphere in a radio frequency furnace (TIG 10/100; Hüttinger Elektronik Freiburg, Germany) at 1000 °C for 12 h. The following starting materials were used as purchased: Amorphous Si 3 N 4 (UBE, SNA-00), AlN (Tokuyama, 99%), Al 2 O 3 (Sigma-Aldrich, 99.9%), SiO 2 (silica gel 60, 0.040–0.063 mm, Merck), and SrH 2 (Materion, 99.9%).…”

Tunable Narrow‐Band Cyan‐Emission of Eu2+‐doped Nitridomagnesophosphates Ba3−xSrx[Mg2P10N20] : Eu2+ (x=0–3)

“…In general, the observed luminescence properties of the solid solution series Ba 3À x Sr x [Mg 2 P 10 N 20 ] : Eu 2 + (x = 0-3) can be compared with other narrow-band nitride-based phosphors, such as BaSi 2 O 2 N 2 : Eu 2 + (Ba222, λ max = 494 nm, fwhm � 35 nm), Sr[Be 6 ON 4 ] : Eu 2 + (λ max = 495 nm, fwhm � 35 nm) or β-MgSrP 3 N 5 O 2 (λ max = 502 nm, fwhm � 42 nm), which have been discussed in the literature as promising candidates for closing the so-called cyan gap in white light-emitting diodes (pc-wLEDs). [10,32,37] In addition to an optimum emission position, a very small Stokes shift, high thermal stability and high conversion efficiency are also necessary for optimum excitation with blue light. However, we have so far investigated the internal quantum efficiency (IQE) and general thermal properties (temperature-dependent PL spectra and high-temperature resistance (HTXRD)) only for the terminal representative with x = 0 (1 mol % Eu 2 + concentration referred to Ba) in bulk.…”

“…[8,9] However, the introduction of further NFCs not only influences the degree of condensation but also opens opportunities for creating novel host structures and coordination environments for the activator sites, to enable unique luminescence properties for suitable activator ions such as Eu 2 + . [10,11] The observed luminescence in Eu 2 + -doped phosphors results from transitions between the excited state 4f 6 ( 7 F)5d 1 and the ground state 4f 7 ( 8 S 7/2 ) of the activator ion, where the energy of the lowest excited state of Eu 2 + ions in a host lattice is highly affected by the local environment due to the nephelauxetic effect and crystal field splitting. [12][13][14] Based on this, our study aims to contribute to the growing compositional and structural diversity of tetrahedron-based nitridophosphate phosphors.…”