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Brexanolone, a formulation of the neurosteroid allopregnanolone (ALLO), is approved for treating postpartum depression (PPD) and is being investigated for therapeutic efficacy across numerous neuropsychiatric disorders. Given ALLO’s beneficial effects on mood in women with PPD compared to healthy control women, we sought to characterize and compare the cellular response to ALLO in women with (n = 9) or without (n = 10, i.e., Controls) past PPD, utilizing our previously established patient-derived lymphoblastoid cell lines (LCLs). To mimic in vivo PPD ALLO-treatment, LCLs were exposed to ALLO or DMSO vehicle for 60 h and RNA-sequenced to detect differentially expressed genes (DEGs, pnominal < 0.05). Between ALLO-treated Control and PPD LCLs, 269 DEGs were identified, including Glutamate Decarboxylase 1 (GAD1), which was decreased 2-fold in PPD. Network analysis of PPD:ALLO DEGs revealed enriched terms related to synaptic activity and cholesterol biosynthesis. Within-diagnosis analyses (i.e., DMSO vs. ALLO) detected 265 ALLO-induced DEGs in Control LCLs compared to only 98 within PPD LCLs, with just 11 DEGs overlapping. Likewise, the gene ontologies underlying ALLO-induced DEGs in PPD and Control LCLs were divergent. These data suggest that ALLO may activate unique and opposing molecular pathways in women with PPD, which may be tied to its antidepressant mechanism.

Our study accesses directly information on electronic and optical properties of phosphors such as intragap states and radiative energy levels. It further describes how the applied methods inform design and understanding of new pc-LED phosphors.

Objective We examined the short-term efficacies of three estrogen-like compounds under placebo-controlled conditions in women with perimenopause-related depression (PMD). Methods Women with PMD were randomized in a double-blind parallel design to one of four treatments: transdermal 17-beta estradiol (TE) (100 mcg/d); oral raloxifene (60 mg/d); a proprietary phytoestrogen compound, Rimostil (1,000 mg twice/d); or placebo for 8 weeks. The main outcome measures were the Center for Epidemiology Studies Depression Scale, 17-item Hamilton Rating Scale for Depression (HRSD), and the Beck Depression Inventory completed at each clinic visit. Secondary outcomes included a visual analogue self-rating completed at each clinic visit, and daily self-ratings of hot flush severity. Cognitive tests were performed at pretreatment baseline and at the end of the trial. In the primary analysis, we obtained four repeated measures in each woman in the four treatment arms. Analyses were done with SAS Version 9.4 software (SAS Institute, Inc, Cary, NC), using PROC MIXED (for mixed models). All models included the following four explanatory variables, regardless of whether they were statistically significant: 1) treatment group (TE, raloxifene, Rimostil, placebo); 2) week (W2, W4, W6, W8); 3) treatment group-by-week interaction; and 4) baseline value of the measure being analyzed. The inclusion of additional variables was evaluated individually for each outcome measure. Results Sixty-six women were randomized into the trial, four women dropped out of the trial, and 62 women were included in the final data analysis. No effect of treatment group was observed in either the Center for Epidemiology Studies Depression Scale (P = 0.34) or Beck Depression Inventory (P = 0.27) scores; however, there was a difference in HRSD scores between treatment groups (P = 0.0037) that pair-wise comparisons of the combined weekly scores in each treatment demonstrated TE's beneficial effects on HRSD scores compared with Rimostil (P = 0.0005), and less consistently with placebo (P = 0.099). The average (SD) of the baseline scores for each treatment group on the HRSD was as follows: TE-15.3 (4.5), raloxifene-16.0 (3.7), Rimostil-14.0 (2.7), and placebo-15.2 (3.0). Whereas the HRSD scores after 8 weeks of treatment (least-square means) were TE-5.2(1.1), raloxifene-5.8(1.2), Rimostil-11.2(1.4), and placebo-7.8(1.1). No differences were observed between raloxifene and either TE or placebo in any scale score. HRSD scores in women assigned to TE were improved compared with those on Rimostil during weeks 6 and 8 (P values = 0.0008, 0.0011, respectively). Cognitive testing at week 8 showed that none of the three active treatment groups performed better than placebo. Conclusions This study did not identify significant therapeutic benefits of TE, Rimostil, or raloxifene compared with placebo in PMD. However, improvements in depression ratings were observed between TE compared with Rimostil. Thus, our findings do not support the role of ERbeta compounds in the treatment of PMD (and indeed could suggest a more important role of ERalpha).

(Oxo)Nitridophosphates have recently been identified as a promising compound class for application in the field of solid‐state lighting. Especially, the latest medium‐pressure syntheses under ammonothermal conditions draw attention of the semiconductor and lighting industry on nitridophosphates. In this contribution, we introduce hot isostatic presses as a new type of medium‐pressure synthetic tool, further simplifying nitridophosphate synthesis. In a second step, phosphorus nitride was replaced as starting material by red phosphorus, enabling the synthesis of Ca2PN3 as model compound, starting only from readily available compounds. Moreover, first luminescence investigations on Eu2+‐doped samples reveal Ca2PN3:Eu2+ as a promising broad‐band red‐emitter (λ em=650 nm; fwhm=1972 cm−1). Besides simple handling, the presented synthetic method offers access to large sample volumes, and the underlying reaction conditions facilitate single‐crystal growth, required for excellent optical properties., Hot isostatic pressing is introduced as easy and fast synthetic access to nitridophosphate phosphors, while providing large‐scale quantities. In particular, the calcium nitridophosphate Ca2PN3:Eu2+ was synthesized under medium‐pressure conditions (150 MPa N2, 1200 °C), revealing single crystals with remarkable size (>100 μm) and quality. Further, Ca2PN3:Eu2+ shows a rather narrow deep‐red emission and notable high internal quantum efficiency.

The nitridoberylloaluminate Sr2[BeAl3N5]:Eu2+ was obtained through reaction of the binary nitrides in a hot isostatic press under a pressure of 50 MPa N2 and a temperature of 1400 °C. The crystal s...

Nitridophosphates exhibit an intriguing structural diversity with different structural motifs, for example, chains, layers or frameworks. In this contribution the novel nitridophosphate Sr3 P3 N7 with unprecedented dreier double chains is presented. Crystalline powders were synthesized using the ammonothermal method, while single crystals were obtained by a high-pressure multianvil technique. The crystal structure of Sr3 P3 N7 was solved and refined from single-crystal X-ray diffraction and confirmed by powder X-ray methods. Sr3 P3 N7 crystallizes in monoclinic space group P2/c. Energy-dispersive X-ray and Fourier-transformed infrared spectroscopy were conducted to confirm the chemical composition, as well as the absence of NHx functionality. The optical band gap was estimated to be 4.4 eV using diffuse reflectance UV/Vis spectroscopy. Upon doping with Eu2+ , Sr3 P3 N7 shows a broad deep-red to infrared emission (λem =681 nm, fwhm≈3402 cm-1 ) with an internal quantum efficiency of 42 %.

The ortho‐oxonitridophosphate Ba2PO3N was synthesized under ammonobasic conditions (T = 1070 K, p = 120 MPa) in custom‐built high‐temperature autoclaves, starting from red phosphorus, BaO, NaN3 and KOH. Thus, single crystals of up to several hundred µm were obtained, which were used for single‐crystal X‐ray diffraction. Ba2PO3N [Pnma (no. 62), a = 7.596(2), b = 5.796(1), c = 10.212(3) A, Z = 4] crystallizes in the β‐K2SO4 structure type with non‐condensed [PO3N]4– ions and is isotypic to its lighter homologues EA2PO3N (EA = Ca, Sr). Powder X‐ray diffraction, energy dispersive X‐ray and Fourier Transformed Infrared spectroscopy corroborate the crystal structure. The optical band gap was determined by means of diffuse reflectance UV/Vis spectroscopy to be 4.3 eV. Eu2+ doped samples show green luminescence (λem = 534 nm, fwhm = 85 nm/2961 cm–1) when irradiated with UV light (λexc = 420 nm). However, Ba2PO3N:Eu2+ shows strong thermal quenching, even at room temperature.

We present the first nitridic analogs of micas, namely AE Si 3 P 4 N 10 (NH) 2 ( AE = Mg, Mg 0.94 Ca 0.06 , Ca, Sr), which were synthesized under high-pressure high-temperature conditions at 1400 °C and 8 GPa from the refractory nitrides P 3 N 5 and Si 3 N 4 , the respective alkaline earth amides, implementing NH 4 F as a mineralizer. The crystal structure was elucidated by single-crystal diffraction with microfocused synchrotron radiation, energy-dispersive X-ray spectroscopic (EDX) mapping with atomic resolution, powder X-ray diffraction, and solid-state NMR. The structures consist of typical tetrahedra-octahedra-tetrahedra ( T - O - T ) layers with P occupying T and Si occupying O layers, realizing the rare motif of sixfold coordinated silicon atoms in nitrides. The presence of H, as an imide group forming the SiN 4 (NH) 2 octahedra, is confirmed by SCXRD, MAS-NMR, and IR spectroscopy. Eu 2+ doped samples show tunable narrow-band emission from deep blue to cyan (451 - 492 nm).

The nitridosilicate CaLu[Si 4 N 7-2 x C x O x ] ( x ≈ 0.3) was synthesized by carbothermal reduction and nitridation starting from CaH 2 , Lu 2 O 3 , graphite and amorphous Si 3 N 4 at 1550°C using a radiofrequency furnace. CaLu[Si 4 N 7-2 x C x O x ] ( x ≈ 0.3) crystallizes isotypic to many previously known M II M III Si 4 N 7 compounds in space group P 6 3 mc , which was confirmed by Rietveld refinement based on powder X-ray diffraction data. Incorporation of C into the crystal structure as a result from the carbothermal synthesis route was confirmed via 13 C- and 29 Si-MAS-NMR spectroscopy. For the first time in the M II M III Si 4 N 7 compound class, complementary EDX measurements suggest that simultaneous incorporation of oxygen compensates for the negative charge excess induced by C, resulting in an adjusted sum formula, CaLu[Si 4 N 7-2 x C x O x ] ( x ≈ 0.3). When excited with UV to blue light, CaLu[Si 4 N 7-2 x C x O x ] ( x ≈ 0.3) shows an emission maximum in the blue spectral region ( λ em = 484 nm; fwhm = 4531 cm -1 ) upon doping with Ce 3+ , while Eu 2+ doped CaLu[Si 4 N 7-2 x C x O x ] ( x ≈ 0.3) exhibits a yellow-green emission ( λ em = 548 nm; fwhm = 4026 cm -1 ).

The nitridoberylloaluminate Ba

We present the first nitridic analogs of micas, namely AESi

The nitridophosphates AEP(8)N(14) (AE=Ca, Sr, Ba) were synthesized at 4-5 GPa and 1050-1150 degrees C applying a 1000 t press with multianvil apparatus, following the azide route. The crystal structures of CaP8N14 and SrP8N14 are isotypic. The space group Cmcm was confirmed by powder X-ray diffraction. The structure of BaP8N14 (space group Amm2) was elucidated by a combination of transmission electron microscopy and diffraction of microfocused synchrotron radiation. Phase purity was confirmed by Rietveld refinement. IR spectra are consistent with the structure models and the chemical compositions were confirmed by X-ray spectroscopy. Luminescence properties of Eu2+-doped samples were investigated upon excitation with UV to blue light. CaP8N14 (lambda(em)=470 nm; fwhm=1380 cm(-1)) and SrP8N14 (lambda(em)=440 nm; fwhm=1350 cm(-1)) can be classified as the first ultra-narrow-band blue-emitting Eu2+-doped nitridophosphates. BaP8N14 shows a notably broader blue emission (lambda(em)=417/457 nm; fwhm=2075/3550 cm(-1)).

Barium imidonitridophosphate BaP6N10NH was synthesized at 5 GPa and 1000 degrees C with a high-pressure high-temperature approach using the multianvil technique. Ba(N-3)(2), P3N5 and NH4Cl were used as starting materials, applying a combination of azide and mineralizer routes. The structure elucidation of BaP6N10NH (P6(3), a=7.5633(11), c=8.512(2) angstrom, Z=2) was performed by a combination of transmission electron microscopy and single-crystal diffraction with microfocused synchrotron radiation. Phase purity was verified by Rietveld refinement. H-1 and P-31 solid-state NMR and FTIR spectroscopy are consistent with the structure model. The chemical composition was confirmed by energy-dispersive X-ray spectroscopy and CHNS analyses. Eu2+-doped samples of BaP6N10NH show blue emission upon excitation with UV to blue light (lambda(em)=460 nm, fwhm=2423 cm(-1)) representing unprecedented Eu2+-luminescence of an imidonitride.

The oxonitridosilicates RE6–xCa1.5xSi11N20O (RE = Yb, Lu; x ≈ 2.2) were synthesized starting from REF3, CaH2, and ”Si(NH)2” in a radiofrequency furnace at 1600 or 1400 °C, respectively. The crystal structure was solved and refined from single‐crystal X‐ray diffraction data of dark red Yb6–xCa1.5xSi11N20O crystals in the trigonal space group P31c (no. 159) with a = 9.8281(10), c = 10.5968(13) A and Z = 2. The structure represents a filled variant of the Er6Si11N20O structure type, in which the charge difference caused by substitution of trivalent Yb3+ with bivalent Ca2+ is balanced by occupation of an additional third cation site. Synthesis of Lu6–xCa1.5xSi11N20O:Ce3+ resulted in a yellow powder with yellow luminescence. Powder X‐ray data were analyzed by Rietveld refinement based on the crystal data obtained from Yb6–xCa1.5xSi11N20O. The Ce3+ doped compound exhibits a broad emission (fwhm ≈ 168 nm/≈ 5100 cm–1) with a maximum at λem ≈ 565 nm. The emission extends more in the red spectral range compared to YAG:Ce3+, thus making it an interesting phosphor for warm‐white single phosphor converted light‐emitting diodes (1pcLED) with an improved color rendering index.

The isotypic nitridoberyllates MBe20N14 with M = Sr, Eu, Ba have been synthesized at high temperatures under a N2 atmosphere. The crystal structures were solved and refined from single-crystal X-ra...

The recently introduced nitridophosphate synthesis in a hot isostatic press (HIP) enabled simple access to large‐scale product quantities starting from exclusively commercially available starting materials. Herein, we show that this method is suitable for the synthesis of highly condensed functional nitridophosphates, as well. Hence, the syntheses of the nitridophosphate zeolites Ba3P5N10 X (X=Cl, Br) are presented as proof of concept for this innovative access. Furthermore, samples of unprecedented Sr3P5N10 X (X=Cl, Br) were prepared and characterized to demonstrate the advantages of this synthetic approach over commonly used methods. Luminescence investigations on Eu2+‐doped samples of AE 3P5N10 X (AE=Sr, Ba; X=Cl, Br) were carried out and characteristics of observed emission bands are discussed., Nitridophosphate zeolites AE 3P5N10 X (AE=Sr, Ba; X=Cl, Br) were synthesized under medium‐pressure conditions (150 MPa N2, 1200 °C), extending the range of the degree of condensation for nitridophosphates accessible by hot isostatic pressing from κ=1/3 to 1/2. AE 3P5N10 X:Eu2+ (AE=Sr, Ba; X=Cl, Br) reveals natural‐white to deep‐red emission.

Recently, a number of different structurally related nitrides characterized by pairs of edge-sharing Si-N tetrahedra forming [Si2N6](10-) units have emerged via different synthesis methods. Concurrently, upon doping with rare earth elements (e.g. Eu2+ and Ce3+), numerous applications in the field of luminescent materials were revealed, ranging from the visible spectrum to the near IR. This compound class in turn emphasizes the extraordinary large tuning range with respect to relative composition by formal cation exchange. In this contribution, we study the dynamical stabilities of the existing Si-based nitridotetrelates and hypothetical Ge analogues promising for future synthesis efforts of luminescent materials by means of extensive phonon calculations. Further calculations of electronic and mechanical properties corroborate the fundamental suitability of the predicted compounds for the applications of potential luminescent materials with regard to band gap (E-g) and Debye temperature (Theta(D)). Calculated enthalpies of the reaction provide further beneficial insights for future experimental attempts. Our study hence highlights a potential range of novel stable nitridogermanates with isotypic structures and suitable electronic properties for optoelectronic applications.

The nitridophosphates AEP8N14 (AE=Ca, Sr, Ba) were synthesized at 4–5 GPa and 1050–1150 °C applying a 1000 t press with multianvil apparatus, following the azide route. The crystal structures of CaP8N14 and SrP8N14 are isotypic. The space group Cmcm was confirmed by powder X‐ray diffraction. The structure of BaP8N14 (space group Amm2) was elucidated by a combination of transmission electron microscopy and diffraction of microfocused synchrotron radiation. Phase purity was confirmed by Rietveld refinement. IR spectra are consistent with the structure models and the chemical compositions were confirmed by X‐ray spectroscopy. Luminescence properties of Eu2+‐doped samples were investigated upon excitation with UV to blue light. CaP8N14 (λ em=470 nm; fwhm=1380 cm−1) and SrP8N14 (λ em=440 nm; fwhm=1350 cm−1) can be classified as the first ultra‐narrow‐band blue‐emitting Eu2+‐doped nitridophosphates. BaP8N14 shows a notably broader blue emission (λ em=417/457 nm; fwhm=2075/3550 cm−1)., Shine on: The alkaline earth nitridophosphates AEP8N14 (AE=Ca, Sr, Ba) were synthesized via high‐pressure high‐temperature syntheses at 4–5 GPa and 1075–1150 °C. The crystal structures for AE=Ca, Sr were refined from powder X‐ray diffraction data, while the crystal structure of BaP8N14 was determined from single‐crystal diffraction data collected with microfocused synchrotron radiation. Eu2+‐doped samples show ultra‐narrow‐band blue emission.

Narrow-band red-emitting luminescent CaBa[Li2Al6N8]:Eu2+ for potential application in illumination-grade white-light-emitting diodes (WLEDs) was synthesized by reaction of the metal hydrides and nitrides in molybdenum crucibles in a hot isostatic press. Upon irradiation with high-energy visible light (444 nm), the material exhibits intense red and infrared luminescence (emission maxima, 636–639 nm, 790 nm; full width at half-maximum (fwhm), 1095–1266 cm–1 (48–57 nm), ≈1450 cm–1 (89 nm)). The red emission from Eu occupying the Ba site is nearly optimal for use in WLEDs combining outstanding color rendition and excellent luminous efficacy and the most narrow-band Eu2+ emission observed to date. The infrared emission intensity from Eu occupying the Ca site can be limited by reducing the activator concentration (here, 0.02–5 atom % Eu). CaBa[Li2Al6N8]:Eu2+ crystallizes isotypically with RbNaLi6Si2O8 in the monoclinic space group C2/m (no. 12) with unit cell parameters a = 16.0851(2), b = 6.467 38(4), c = 8.04...

The oxonitridocarbidosilicates RE4Ba2[Si12O2N16C3]:Eu2+ (RE = Lu, Y) were synthesized by carbothermal reactions starting from RE2O3, graphite, Ba2Si5N8, Si(NH)2, and Eu2O3. The crystal structure of...

Beryllate structures are marginally investigated, but show intriguing structural relations to oxo- and nitridosilicates. A typical feature is the coordination of Be in both trigonal planar and tetrahedral coordination by O. A broad range of structures is accessible by variable combinations of both building units. Three novel ternary Sr-oxoberyllates are characterized by single-crystal X-ray diffraction analysis, density functional theory calculations and investigations on luminescence properties: alpha-SrBeO2, beta-SrBeO2 and Sr12Be17O29 are obtained with oxoberyllate substructures, made up of either BeO3 triangles or BeO4 tetrahedra. The compounds can be described as chain- and layer-type beryllates. When excited with blue light of (In,Ga)N LED chips, beta-SrBeO2 and Sr12Be17O29 show visible emission in the yellow and orange spectral range, respectively, upon doping with Eu2+. Exceptional narrow-band yellow emission (lambda(em)=564 nm, fwhm=55 nm) makes beta-SrBeO2:Eu2+ a promising phosphor for application in phosphor-converted (pc-)LEDs.

Ce3+ doped solids find broad application, e.g. in phosphor converted light emitting diodes, utilizing the usually broad blue to yellow-orange emission of the respective phosphors. The red to infrared spectral range was not yet accessible with the activator Ce3+, even in nitride host materials. Here, we report on the nitridolithosilicates Li38.7RE3.3Ca5.7[Li2Si30N59]O2F (RE = La, Ce, Y) with unique, red-shifted Ce3+ luminescence. The materials were synthesized by solid-state metathesis reactions in tantalum ampules. The isotypic crystal structures exhibit a highly condensed three-dimensional network made up of SiN4 and LiN4 tetrahedra. Crystal structures were refined from single-crystal and powder X-ray diffraction data. The results are supported by energy-dispersive X-ray spectroscopy as well as charge distribution, lattice energy, and bond valence sum calculations. Optical band gaps of ≈4 eV were determined from diffuse reflectance UV/vis data using Tauc plots. The nitridolithosilicates are highly excita...

Highly efficient phosphor-converted light-emitting diodes (pc-LEDs) are popular in lighting and high-tech electronics applications. The main goals of present LED research are increasing light quality, preserving color point stability and reducing energy consumption. For those purposes excellent phosphors in all spectral regions are required. Here, we report on ultra-narrow band blue emitting oxoberyllates AELi(2)[Be4O6]:Eu2+ (AE=Sr,Ba) exhibiting a rigid covalent network isotypic to the nitridoalumosilicate BaLi2[(Al2Si2)N-6]:Eu2+. The oxoberyllates' extremely small Stokes shift and unprecedented ultra-narrow band blue emission with fwhm approximate to 25nm (approximate to 1200cm(-1)) at (em)=454-456nm result from its rigid, highly condensed tetrahedra network. AELi(2)[Be4O6]:Eu2+ allows for using short-wavelength blue LEDs ((em)

M[BeSi2N4] (M=Sr,Eu), crystallizing in the hexagonal space group P (6) over bar 2c, was synthesized from Sr(NH2)(2), Be3N2, and "Si(NH)(2)" in W crucibles under a N-2 atmosphere in a radio-frequency furnace. The crystal structure was solved from powder X-ray diffraction data by the charge-flipping method (Sr[BeSi2N4]: a=4.86082(2), c=9.42264(4)angstrom, Z=2;Eu[BeSi2N4]: a=4.85848(1), c=9.41615(4)angstrom). M[BeSi2N4] contains a highly condensed rigid network of trigonal planar [BeN3] units that are connected to Si2N7 double tetrahedra by common vertices. M[BeSi2N4] (M=Sr,Eu) are the first examples of nitridoberyllosilicates and are isotypic to the oxoberyllate Sr[Be3O4]. Eu2+-doped Sr[BeSi2N4] and Eu[BeSi2N4] show orange-trapped exciton emission (lambda(em)=605nm, fwhm approximate to 126nm), whereas Ce3+-doped samples of Sr[BeSi2N4] show nontypical yellowish-orange luminescence. Sr[BeSi2N4] has a large band gap of approximate to 4.4eV and shows high chemical and thermal stability. Eu2+-doped beryllates with regular 4f(6)5d(1)4f(7)-emission could be interesting for future application in LEDs upon doping with Eu2+ or Ce3+ due to large band gaps, rigid networks, and chemical and thermal stability.

Oxo- and (oxo)nitridoberyllates show exceptional potential as host lattices for application in illumination grade phosphor converted (pc)LEDs due to their remarkable electronic and structural characteristics, allowing highly efficient narrow-band emission upon doping with Eu2+. Sr[Be6ON4]:Eu2+, the first example of an oxonitridoberyllate phosphor, exhibits narrow-band cyan emission (λem = 495 nm; full width at half-maximum, fwhm = 35 nm; ≈1400 cm–1), comparable to the emission of the oxonitridosilicate BaSi2O2N2:Eu2+ (fwhm = 35 nm) or a cyan-emitting primary LED (fwhm = 27 nm). Sr[Be6ON4]:Eu2+ reveals a highly condensed rigid 3D network with a remarkably large degree of condensation [i.e., atomic ratio Be:(O,N)] of κ = 1.2 that is achieved by interconnection of highly condensed layers of BeN4 tetrahedra by Be2ON6 units via common edges. The crystal structure of Sr[Be6ON4]:Eu2+ was solved on the basis of single-crystal and powder XRD data (C2/c, no. 15, a = 13.9283(14), b = 5.7582(6), c = 4.9908(5) A, β = ...

Red-emitting phosphors with the general sum formula Sr8[Li(2–0.5x)MgxAl(22–0.5x)N28]:Eu2+ for application in warm-white illumination grade light emitting diodes were obtained by reacting the metals, hydrides, and nitrides in molybdenum crucibles in a hot isostatic press. Upon irradiation with blue light (440 nm), the materials exhibit red luminescence (emission maximum: 633–665 nm; full width at half-maximum (fwhm): 1736–1964 cm–1, 78–82 nm) tunable by adjusting the compositional variable x (here, 2 and 4) as well as the activator concentration (here, 0.075–1 atom-% Eu2+). The materials show promising thermal behavior of the emission with relative quantum efficiencies, compared to room temperature, of 66% (x = 0) and 84% (x = 2) at 200 °C. α-Sr8[Li(2–0.5x)MgxAl(22–0.5x)N28]:Eu2+ (x = 2 and 4) crystallizes isotypically with Sr4[LiAl11N14]:Eu2+ in the orthorhombic space group Pnnm (no. 58) with unit cell parameters a = 10.51818(5)–10.54878(6), b = 10.44513(5)–10.48253(6), and c = 3.25704(1)–3.272752(15) A. ...

The oxonitridosilicate oxides Y4Ba2[Si9ON16]O:Eu2+ and Lu4Ba2[Si9ON16]O:Eu2+ have been synthesized starting from REF3, RE2O3 (RE = Y, Lu), BaH2, Si(NH)2, and EuF3 in a radiofrequency furnace at 1550 °C. The crystal structures were solved and refined from single-crystal X-ray data supported with Rietveld refinement on X-ray powder diffraction data. Both compounds are isotypic and crystallize in monoclinic space group P21/c (no. 14) with Z = 4 and a = 6.0756(2), b = 27.0606(9), c = 9.9471(3) A, and β = 91.0008(8)° for RE = Y and a = 6.0290(3), b = 26.7385(12), c = 9.8503(5) A, and β = 90.7270(30)° for RE = Lu. The unique crystal structure exhibits a three-dimensional network made up from Q4-type SiN4 and Q3-type SiON3 tetrahedra. Containing 4-fold bridging N[4] atoms in star-shaped units [N[4](SiN3)4] next to N[3], N[2], O[1], and noncondensed oxide ions, the title compounds illustrate the vast structural variety in (oxo)nitridosilicates. Under excitation with UV to blue light, Y4Ba2[Si9ON16]O:Eu2+ shows em...

Highly efficient narrow-band red emitting (RE) phosphors are the most desired and requested materials for developing illumination grade phosphor-converted light emitting diodes (pcLEDs). This study presents direct measurements of RE energy levels, critical to the color and efficiency of LED phosphors. For the first time, we experimentally determine the energetic separation of the Eu 5d state and the conduction band, which is the key indicator of quantum efficiency. This was achieved for the next-generation pcLED phosphors Li2Ca2[Mg2Si2N6]:Eu2+, Ba[Li2(Al2Si2)N6]:Eu2+, and Sr[LiAl3N4]:Eu2+ using resonant inelastic X-ray scattering. Band to band and 4f to valence band transitions are directly observed in X-ray excited optical luminescence spectra of Sr[LiAl3N4]:Eu2+ and Sr[Mg3SiN4]:Eu2+. These techniques are widely applicable and create a comprehensive, experimental picture of the Eu2+ energy levels in these compounds, leading to a complete understanding of all pertinent electronic processes. This study for...

A large band gap is a prerequisite for efficient emissions from a rare earth doped phosphor and is consequently a prerequisite for its application in high-quality lighting. We present a detailed characterization of luminescent materials Li2Ca2[Mg2Si2N6]:Eu2+ and Ba[Li2(Al2Si2)N6]:Eu2+ using soft X-ray spectroscopy and density functional theory calculations, including a rigorous experimental determination, and theory-based elucidation, of their band gaps. The band gap of Li2Ca2[Mg2Si2N6]:Eu2+ is determined to be 4.84 ± 0.20 eV, while that of Ba[Li2(Al2Si2)N6]:Eu2+ is 4.82 ± 0.20 eV. The origin of the band gaps is discussed in the context of the calculated DOS of each material and compared to benchmark luminescent materials Sr[LiAl3N4]:Eu2+ and Sr[Mg3SiN4]:Eu2+. Critically, the elements determining the band gaps are identified using the calculated density of states, as well as experimental resonant X-ray emission measurements. This allows for predictive power when searching for new nitridosilicates and rela...

Nitridophosphates exhibit an intriguing structural diversity with different structural motifs, for example, chains, layers or frameworks. In this contribution the novel nitridophosphate Sr3P3N7 with unprecedented dreier double chains is presented. Crystalline powders were synthesized using the ammonothermal method, while single crystals were obtained by a high‐pressure multianvil technique. The crystal structure of Sr3P3N7 was solved and refined from single‐crystal X‐ray diffraction and confirmed by powder X‐ray methods. Sr3P3N7 crystallizes in monoclinic space group P2/c. Energy‐dispersive X‐ray and Fourier‐transformed infrared spectroscopy were conducted to confirm the chemical composition, as well as the absence of NHx functionality. The optical band gap was estimated to be 4.4 eV using diffuse reflectance UV/Vis spectroscopy. Upon doping with Eu2+, Sr3P3N7 shows a broad deep‐red to infrared emission (λem=681 nm, fwhm≈3402 cm−1) with an internal quantum efficiency of 42 %., Nitridophosphates: A complementary approach of medium‐ and high‐pressure methods with their respective advantages was used for the synthesis of Sr3P3N7, indicating this strategy as promising for further investigation of novel nitridophosphates. Upon doping with Eu2+, Sr3P3N7 exhibits luminescence in the deep‐red region.

Barium imidonitridophosphate BaP6N10NH was synthesized at 5 GPa and 1000 °C with a high‐pressure high‐temperature approach using the multianvil technique. Ba(N3)2, P3N5 and NH4Cl were used as starting materials, applying a combination of azide and mineralizer routes. The structure elucidation of BaP6N10NH (P63, a=7.5633(11), c=8.512(2) Å, Z=2) was performed by a combination of transmission electron microscopy and single‐crystal diffraction with microfocused synchrotron radiation. Phase purity was verified by Rietveld refinement. 1H and 31P solid‐state NMR and FTIR spectroscopy are consistent with the structure model. The chemical composition was confirmed by energy‐dispersive X‐ray spectroscopy and CHNS analyses. Eu2+‐doped samples of BaP6N10NH show blue emission upon excitation with UV to blue light (λ em=460 nm, fwhm=2423 cm−1) representing unprecedented Eu2+‐luminescence of an imidonitride., The imidonitridophosphate BaP6N10NH was synthesized via high‐pressure high‐temperature approach at 4 GPa and 1150 °C. The crystal structure was determined from single‐crystal diffraction data collected with microfocused synchrotron radiation. Doping of the title compound with Eu2+ leads to unprecedented observation of luminescence from a Eu2+‐doped imidonitridophosphate.

Recently, a number of different structurally related nitrides characterized by pairs of edge-sharing Si-N tetrahedra forming [Si

The nitridomagnesosilicates Li2Ca2[Mg2Si2N6]:Eu2+ and Li2(Ca1.88Sr0.12)[Mg2Si2N6]:Eu2+ show narrow-band red emission at 638 and 634 nm, respectively, with an emission bandwidth of 62 nm (∼1513 cm–1) after excitation in the blue spectral region. Ce3+-doped samples show luminescence in the green spectral range (λem = 540 nm). The compounds were synthesized via solid-state metathesis reaction in Li melts. Refinement of single-crystal X-ray diffraction data revealed that Li2(Ca1.88Sr0.12)[Mg2Si2N6] crystallizes isomorphic to Li2Ca2[Mg2Si2N6]: C2/m [Z = 2, a = 5.5744(2), b = 9.8439(3), c = 6.0170(2) A, β = 97.2520(10)°, R1 = 0.021, wR2 = 0.047]. Crystal composition was checked by EDS and ICP-OES measurements and luminescence properties are compared to state of the art narrow-band red emitting luminophors. On the basis of its narrow-band emission, application of the novel red luminophor in high CRI white pcLEDs is promising.

Droop, the decrease of efficiency with increased power density, became a major topic with InGaN LEDs, after its introduction in 2007. This paper provides insight into droop in localized center luminescence phosphors, exemplified here by Eu2+ doped materials. This topic is of increasing importance, as high brightness blue LEDs have reached outputs >1 W/mm2. The nonlinearities in phosphor quantum efficiency result in drive-dependent color point shift and reduction of overall efficiency of phosphor converted white LEDs which utilize Eu2+ activated phosphors. The efficiency quenching can be traced back to two processes, well-known in laser physics, excited state absorption or/and cross relaxation by Foerster/Dexter transfer. Both processes lead to reduction in phosphor efficiency, but they can be differentiated. Understanding the root cause of efficiency quenching opens ways to minimize the practical consequences. (© 2016 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim)

Highly efficient red-emitting luminescent materials deliver the foundation for next-generation illumination-grade white light-emitting diodes (LEDs). Recent studies demonstrate that the hardly explored class of nitridoaluminates comprises intriguing phosphor materials, e.g., Sr[LiAl3N4]:Eu2+ or Ca[LiAl3N4]:Eu2+. Here, we describe the novel material Ca18.75Li10.5[Al39N55]:Eu2+ with highly efficient narrow-band red emission (λem ≈ 647 nm, full width at half-maximum, fwhm ≈ 1280 cm–1). This compound features a rather uncommon crystal structure, comprising sphalerite-like T5 supertetrahedra that are composed of tetrahedral AlN4 units that are interconnected by additional AlN4 moieties. The network charge is compensated by Ca2+ and Li+ ions located between the supertetrahedra. The crystal structure was solved and refined from single-crystal and powder X-ray diffraction data in the cubic space group Fd3m (No. 227) with a = 22.415(3) A and Z = 8. To verify the presence of Li, transmission electron microscopy (T...

We report on the structure and properties of the lithium oxonitridosilicate oxide Li

The oxonitridocarbidosilicates RE

Beryllate structures are marginally investigated, but show intriguing structural relations to oxo- and nitridosilicates. A typical feature is the coordination of Be in both trigonal planar and tetrahedral coordination by O. A broad range of structures is accessible by variable combinations of both building units. Three novel ternary Sr-oxoberyllates are characterized by single-crystal X-ray diffraction analysis, density functional theory calculations and investigations on luminescence properties: α-SrBeO