12136-60-6Relevant articles and documents
Li7Cd4.5Ge4Se16 and Li6.4Cd4.8Sn4Se16: Strong Nonlinear Optical Response in Quaternary Diamond-Like Selenide Networks
Guo, Yangwu,Li, Xiaoshuang,Feng, Kai,Li, Chao,Zhou, Molin,Wu, Yicheng,Yao, Jiyong
, p. 871 - 876 (2018)
Two new selenides with diamond-like structures, Li7Cd4.5Ge4Se16 and Li6.4Cd4.8Sn4Se16, were synthesized by using a conventional high-temperature solid-state reaction m
Organosilicon chalcogenides with trisilane units - Bicyclo[3.3.1]nonanes, bicyclo[3.2.2]nonanes and spiro[4.4]nonanes
Herzog, Uwe,Borrmann
, p. 564 - 574 (2004)
Treatment of 1,2,3-trichloropentamethyltrisilane (1) with H2S/NEt3 results in the formation of a mixture of two isomers of (Me5Si3)2 S3 with a bicyclo[3.3.1]nonane (2a) and a bicyclo[3.2.2]nonane (2b) skeleton, while the reaction of 1 with Li2Se yields one product only, (Me5 Si3)2Se3 (3a), with a bicyclo[3.3.1]nonane structure. Besides 1H, 13C, 29Si and 77Se NMR spectroscopy 3a has also been characterized by a crystal structure analysis. Compounds Si(SiMe2EMR2E)2 (5a-h: MR2: SiMe2 (5a, c, d), SiPh2 (5b), GeMe2 (5e, f), SnMe2 (5g, h); E=S (5a, b, e, g), Se (5c, f, h), Te (5d)) with a spiro[4.4]nonane skeleton have been obtained in mixture with varying amounts of the corresponding six-membered rings (R2ME)3 by reactions of mixtures of 1,2,2,3-tetrachlorotetramethyltrisilane (4) and diorganodichlorosilanes, Me2GeCl2 or Me2SnCl2, with H2S/NEt3, Li2Se or Li2Te and have been characterized in situ by multinuclear NMR spectroscopy (1H, 13C, 29Si, 119Sn, 77Se, 125Te) and GC-MS.
Two-Dimensional Substitution: Toward a Better Understanding of the Structure-Transport Correlations in the Li-Superionic Thio-LISICONs
Minafra, Nicolò,Hogrefe, Katharina,Barbon, Federico,Helm, Bianca,Li, Cheng,Wilkening, H. Martin R.,Zeier, Wolfgang G.
, p. 727 - 740 (2021)
A deeper understanding of the relationships among composition-structure-transport properties in inorganic solid ionic conductors is of paramount importance to develop highly conductive phases for future employment in solid-state Li-ion battery applications. To shed light on the mechanisms that regulate these relationships, in this work, we perform a two-dimensional substitution series in the thio-LISICON family Li4Ge1-xSnxS4-ySey. The structural modifications brought up by the elemental substitutions were investigated via Rietveld refinements against high-resolution neutron diffraction data that allowed a precise characterization of the anionic framework and lithium substructure. The analyses show that the anionic and cationic substitutions influence the polyhedral and unit cell volumes in different fashions and that the size of the polyanionic groups alone is not enough to describe lattice expansion in these materials. Moreover, we show that the lithium disorder that is crucial to achieve fast ionic mobility may be correlated to the lithium polyhedral volumes. The correlation of these structural modifications with the transport properties, investigated via electrochemical impedance spectroscopy and 7Li nuclear magnetic resonance spin-lattice relaxation measurements, shows a nonmonotonic behavior of the ionic conductivity and activation energy against the lithium polyhedral volumes, hinting to an optimal size of the conduction pathways for the ionic diffusion. Ultimately, the results obtained in this work will help to establish new guidelines for the optimization of solid electrolytes and gain a more profound understanding of the influence of the substituents on the structure and transport properties of Li-ion conductors.
Room-temperature synthesis, hydrothermal recrystallization, and properties of metastable stoichiometric FeSe
Nitsche,Goltz,Klauss,Isaeva,Mueller,Schnelle,Simon,Doert, Th.,Ruck
, p. 7370 - 7376 (2012)
Room-temperature precipitation from aqueous solutions yields the hitherto unknown metastable stoichiometric iron selenide (ms-FeSe) with tetragonal anti-PbO type structure. Samples with improved crystallinity are obtained by diffusion-controlled precipitation or hydrothermal recrystallization. The relations of ms-FeSe to superconducting η-FeSe1-x and other neighbor phases of the iron-selenium system are established by high-temperature X-ray diffraction, DSC/TG/MS (differential scanning calorimetry/ thermogravimetry/mass spectroscopy), 57Fe Moessbauer spectroscopy, magnetization measurements, and transmission electron microscopy. Above 300 °C, ms-FeSe decomposes irreversibly to η-FeSe1-x and Fe7Se8. The structural parameters of ms-FeSe (P4/nmm, a = 377.90(1) pm, c = 551.11(3) pm, Z = 2), obtained by Rietveld refinement, differ significantly from literature data for η-FeSe1-x. The Moessbauer spectrum rules out interstitial iron atoms or additional phases. Magnetization data suggest canted antiferromagnetism below TN = 50 K. Stoichiometric non-superconducting ms-FeSe can be regarded as the true parent compound for the 11 iron-chalcogenide superconductors and may serve as starting point for new chemical modifications.
Cyclic Silylselenides: Convenient Selenium Precursors for Atomic Layer Deposition
Charvot, Jaroslav,Pokorny, Daniel,Zazpe, Raul,Krumpolec, Richard,Pavliňák, David,Hromádko, Luděk,P?ikryl, Jan,Rodriguez-Pereira, Jhonatan,Klikar, Milan,Jelínková, Veronika,Macak, Jan M.,Bure?, Filip
, p. 576 - 579 (2020)
Three cyclic silylselenides were prepared in a straightforward manner. Property tuning has been achieved by varying the ring size and the number of embedded selenium atoms. All silylselenides possess improved resistance towards moisture and oxidation as well as high thermal robustness and sufficient volatility with almost zero residues. The six-membered diselenide proved to be particularly superior Se precursors for atomic layer deposition and allowed facile preparation of MoSe2 layers. Their structure and composition have been investigated by Raman and X-ray photoelectron spectroscopy as well as scanning electron microscopy revealing vertically aligned flaky shaped nanosheets.
Deposition of MoSe2flakes using cyclic selenides
Bure?, Filip,Charvot, Jaroslav,Jelínková, Veronika,Klikar, Milan,Krumpolec, Richard,Macak, Jan M.,Pavliňák, David,Pokorny, Daniel,Rodriguez-Pereira, Jhonatan,Zazpe, Raul
, p. 22140 - 22147 (2021)
The currently limited portfolio of volatile organoselenium compounds used for atomic layer deposition (ALD) has been extended by designing and preparing a series of four-, five- and six-membered cyclic silylselenides. Their fundamental properties were tailored by alternating the ring size, the number of embedded Se atoms and the used peripheral alkyl chains. In contrast to former preparations based on formation of sodium or lithium selenides, the newly developed synthetic method utilizes a direct and easy reaction of elemental selenium with chlorosilanes. Novel 2,2,4,4-tetraisopropyl-1,3,2,4-diselenadisiletane, which features good trade-off between chemical/thermal stability and reactivity, has been successfully used for gas-to-solid phase reaction with MoCl5affording MoSe2. A thorough characterization of the as-deposited 2D MoSe2flakes revealed its out-of-plane orientation and high purity. Hence, the developed four-membered cyclic silylselenide turned out to be well-suited Se-precursor for ALD of MoSe2
Direct thermal neutron detection by the 2D semiconductor 6LiInP2Se6
Chica, Daniel G.,He, Yihui,McCall, Kyle M.,Chung, Duck Young,Pak, Rahmi O.,Trimarchi, Giancarlo,Liu, Zhifu,De Lurgio, Patrick M.,Wessels, Bruce W.,Kanatzidis, Mercouri G.
, p. 346 - 349 (2020)
Highly efficient neutron detectors are critical in many sectors, including national security1,2, medicine3, crystallography4 and astronomy5. The main neutron detection technologies currently used involve 3He-gas-filled proportional counters6 and light scintillators7 for thermalized neutrons. Semiconductors could provide the next generation of neutron detectors because their advantages could make them competitive with or superior to existing detectors. In particular, solids with a high concentration of high-neutron-capture nuclides (such as 6Li, 10B) could be used to develop smaller detectors with high intrinsic efficiencies. However, no promising materials have been reported so far for the construction of direct-conversion semiconductor detectors. Here we report on the semiconductor LiInP2Se6 and demonstrate its potential as a candidate material for the direct detection of thermal neutrons at room temperature. This compound has a good thermal-neutron-capture cross-section, a suitable bandgap (2.06 electronvolts) and a favourable electronic band structure for efficient electron charge transport. We used α particles from an 241Am source as a proxy for the neutron-capture reaction and determined that the compact two-dimensional (2D) LiInP2Se6 detectors resolved the full-energy peak with an energy resolution of 13.9 per cent. Direct neutron detection from a moderated Pu–Be source was achieved using 6Li-enriched (95 per cent) LiInP2Se6 detectors with full-peak resolution. We anticipate that these results will spark interest in this field and enable the replacement of 3He counters by semiconductor-based neutron detectors.
Soluble semiconductors AAsSe2 (A = Li, Na) with a direct-band-gap and strong second harmonic generation: A Combined experimental and theoretical study
Bera, Tarun K.,Jang, Joon I.,Song, Jung-Hwan,Malliakas, Christos D.,Freeman, Arthur J.,Ketterson, John B.,Kanatzidis, Mercouh G.
, p. 3484 - 3495 (2010)
AAsSe2 (A = Li, Na) have been identified as a new class of polar direct-band gap semiconductors. These I - V - Vl2 ternary alkali-metal chalcoarsenates have infinite single chains of (1/∞)[AsQ 2] derived from corner-sharing pyramidal AsQ3 units with stereochemically active lone pairs of electrons on arsenic. The conformations and packing of the chains depend on the structure-directing alkali metals. This results in at least four different structural types for the Li1 xNaxAsSe2 stoichoimetry (α-LiAsSe 2, β-LiAsSe2, γ-NaAsSe2, and δ-NaAsSe2). Single-crystal X-ray diffraction studies showed an average cubic NaCI-type structure for (α-LiAsSe2, which was further demonstrated to be locally distorted by pair distribution function (PDF) analysis. The β and γ forms have polar structures built of different (1/∞)[AsSe2] chain conformations, whereas the δ form has nonpolar packing. A wide range of direct band gaps are observed, depending on composition: namely, 1.11 eV for (α-LiAsSe2, 1.60 eV for LiAsS2, 1.75 eV for γ-NaAsSe2, 2.23 eV for NaAsS2. The AAsQ2 materials are soluble in common solvents such as methanol, which makes them promising candidates for solution processing. Band structure calculations performed with the highly precise screenedexchange sX-LDA FLAPW method confirm the direct-gap nature and agree well with experiment. The polar y-NaAsSe2 shows very large nonlinear optical (NLO) second harmonic generation (SHG) response in the wavelength range of 600-950 nm. The theoretical studies confirm the experimental results and show that y-NaAsSe2 has the highest static SHG coefficient known to date, 337.9 pm/V, among materials with band gaps larger than 1.0 eV.
Extended Chemical Flexibility of Cubic Anti-Perovskite Lithium Battery Cathode Materials
Lai, Kwing To,Antonyshyn, Iryna,Prots, Yurii,Valldor, Martin
, p. 13296 - 13299 (2018)
Novel bichalcogenides with the general composition (Li2TM)ChO (TM = Mn, Co; Ch = S, Se) were synthesized by single-step solid-state reactions. These compounds possess cubic anti-perovskite crystal structure with Pm3m symmetry; TM and Li are disordered on the crystallographic site 3c. According to Goldschmidt tolerance factor calculations, the available space at the 3c site is too large for Li+ and TM2+ ions. As cathode materials, all title compounds perform less prominent in lithium-ion battery setups in comparison to the already known TM = Fe homologue; e.g., (Li2Co)SO has a charge density of about 70 mAh g-1 at a low charge rate. Nevertheless, the title compounds extend the chemical flexibility of the anti-perovskites, revealing their outstanding chemical optimization potential as lithium battery cathode material.
Synthesis, Structure and Application of Intramolecularly-Coordinated Gallium Chalcogenides: Suitable Single-Source precursors for GaxSey Materials
?i?ica, Tomá?,Bene?, Ludvík,Bou?ka, Marek,Dostál, Libor,Jambor, Roman,Knotek, Petr,Macak, Jan M.,Němec, Petr,R??i?ková, Zdenka,Ruleová, Pavlína
, p. 14470 - 14476 (2018)
Studies have been focused on the synthesis of N→Ga-coordinated organogallium selenides and tellurides [L1Ga(μ-Se)]2 (1), [L2Ga(μ-Se)]2 (2) and [L1Ga(μ-Te)]2 (3), respectively, containing either N,C,N- or C,N-chelating ligands L1, 2 (L1 is {2,6-(Me2NCH2)2C6H3}? and L2 is {2-(Et2NCH2)-4,6-tBu2-C6H2}?) having Ga/E (E=Se or Te) atoms in 1/1 ratio. To change the Ga/E ratio, an unusual N→Ga-coordinated organogallium tetraselenide L1Ga(κ2-Se4) (4) was prepared. An unprecedented complex (L1Ga)2(μ-Te2)(μ-Te) (5), as the result of the non-stability of 3, was also isolated. Compound 2 is a suitable single-source precursor for the preparation of amorphous GaSe thin films by the spin coating. Moreover, simple heating of an octadecylamine solution of 2 provided, after work up, monoclinic Ga2Se3 crystals with different crystallinity according to conditions used. Therefore, compound 2 may be also used as a source of Ga2Se3 in the low-temperature doping process of Bi2Se3.
