Combination of a solvent–salt complex [acetonitrile(ACN)2–LiTFSI] with a hydrofluoroether (HFE) co-solvent unveils a new class of Li–S battery electrolytes that possess essentially no solubility for lithium polysulfides, yet exhibit excellent capacity and very good rate capability..

The oxide garnet Y3Al5O12 (YAG), when substituted with a few percent of the activator ion Ce3+ to replace Y3+, is a luminescent material that is nearly ideal for phosphor-converted solid-state white lighting. The local environments of the small number of substituted Ce3+ ions are known to critically influence the optical properties of the phosphor. Using a combination of powerful experimental methods, the nature of these local environments is determined and is correlated with the macroscopic luminescent properties of Ce-substituted YAG. The rigidity of the garnet structure is established and is shown to play a key role in the high quantum yield and in the resistance toward thermal quenching of luminescence. Local structural probes reveal compression of the Ce3+ local environments by the rigid YAG structure, which gives rise to the unusually large crystal-field splitting, and hence yellow emission. Effective design rules for finding new phosphor materials inferred from the results establish that efficient phosphors require rigid, highly three-dimensionally connected host structures with simple compositions that manifest a low number of phonon modes, and low activator ion concentrations to avoid quenching.

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Yb(3)AuGe(2)In(3) was obtained as large single crystals in high yield from reactions run in liquid indium. Single crystal X-ray diffraction data show that Yb(3)AuGe(2)In(3) is an ordered variant of YbAuIn with lattice constants, a = b = 7.3153(8) Å and c = 4.4210(5) Å, and space group P(6)2m. The parent compound YbAuIn was also studied for comparison. YbAuIn crystallizes in the ZrNiAl structure type, hexagonal, P(6)2m space group with lattice parameters a = b = 7.7127(11) Å and c = 4.0294(8) Å. In Yb(3)AuGe(2)In(3), Ge substitutes for one of the two Au positions in the ternary compound Yb(3)Au(3)In(3). The structure can be described as alternating [Ge(2)In(3)] and [Yb(3)Au] slabs that stack along the c-axis. The magnetic susceptibility data follow a modified Curie-Weiss law. The effective magnetic moment μ(eff) of 0.52 μ(B)/Yb atom was deduced from the Curie constant and Curie-Weiss constant of θ(p) = -1.5 K indicating antiferromagnetic interactions in Yb(3)AuGe(2)In(3). X-ray absorption near edge spectroscopy (XANES) measurements indicate intermediate valency for Yb in both compounds. The metallic nature of both compounds was confirmed by the resistivity measurements. Specific heat data for Yb(3)AuGe(2)In(3) and YbAuIn give an electronic γ term of 31 and 84 mJ/mol·K(2), respectively, suggesting that the ternary analog is a "light" heavy fermion compound.

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Local Environments of Dilute Activator Ions in the Solid-State Lighting PhosphorY3-xCexAl5O12. -Ce-doped yttrium aluminum garnet (Ce:YAG), CexY3-xAl5O12 with x = 0-0.09, is prepared by solid state synthesis using stoichiometric amounts of Y2O3, Al2O3, and CeO2 plus an optimum of 5 wt% each of BaF2 and NH4F as sintering aids (alumina crucible, 1500°C, 5 h, 5% H2/N2 atmosphere). Using a combination of powerful experimental methods, the nature of Ce 3+ local environments is determined and is correlated with the macroscopic luminescent properties of Ce:YAG. The rigidity of the garnet structure is discussed to play a key role in the high quantum yield and in the resistance towards thermal luminescence quenching. Local structural probes reveal compression of the Ce 3+ local environments by the rigid YAG structure which gives rise to the unusually large crystal-field splitting and hence yellow emission. Effective design rules for finding new phosphors require rigid, highly three-dimensionally connected host structures with simple compositions that manifest a low number of phonon modes and low activator ion concentrations to avoid quenching. -(GEORGE, N. C.; PELL, A. J.; DANTELLE, G.; PAGE, K.; LLOBET, A.; BALASUBRAMANIAN, M.; PINTACUDA, G.; CHMELKA*, B. F.; SESHADRI, R.; Chem. Mater. 25 (2013) 20, 3979-3995, http://dx.