Massive hydration-driven swelling of layered perovskite niobate crystals in aqueous solutions of organo-ammonium bases.

Osmotic swelling behaviors in layered perovskite niobate were examined in aqueous solutions containing three types of amine-related agents including quaternary ammonium hydroxides and tertiary aminoethanol. Platelet microcrystals of a protonated layered perovskite niobate, HCaNbO·1.5HO, were found to show enormous swelling in the aqueous solutions, which was clearly recognized by the noticeable expansion of the sample volume over 100-fold.

Accordion-like swelling of layered perovskite crystals via massive permeation of aqueous solutions into 2D oxide galleries.

Platelet crystals of a layered perovskite showed massive accordion-like swelling in a tetrabutylammonium hydroxide solution. The permeation of the solution induced the huge expansion of the interlayer spacing as well as the crystal thickness up to 50-fold, leading to a very high water content of >90 wt%.

Efficient photoinduced charge accumulation in reduced graphene oxide coupled with titania nanosheets to show highly enhanced and persistent conductance.

Tuning of the electrical properties of graphene via photoexcitation of a heteroassembled material has started to attract attention for electronic and optoelectronic applications. Actually photoinduced carrier doping from the hexagonal boron nitride (h-BN) substrate greatly modulated the transport property of the top layer graphene, showing promising potential for this approach. However, for practical applications, the large scale production of this two-dimensional heterostructure is needed.

Tuning the surface charge of 2D oxide nanosheets and the bulk-scale production of superlatticelike composites.

The surface charge of various anionic unilamellar nanosheets, such as graphene oxide (GO), Ti0.87O2(0.52-), and Ca2Nb3O10(-) nanosheets, has been successfully modified to be positive by interaction with polycations while maintaining a monodispersed state.

Superlattice assembly of graphene oxide (GO) and titania nanosheets: fabrication, in situ photocatalytic reduction of GO and highly improved carrier transport.

Two different kinds of two-dimensional (2D) materials, graphene oxide (GO) and titanium oxide nanosheets (Ti₀.₈₇O2(0.52-)), were self-assembled layer-by-layer using a polycation as a linker into a superlattice film.

Partial alkali-metal ion extraction from K0.8(Li0.27Ti1.73)O4 using PTFE as an extraction reagent.

The alkali-metal ion extraction ability of an inert material, polytetrafluoroethylene (PTFE; empirical formula CF2), was clarified by characterizing a partially alkali-metal ion-extracted layered compound, K0.8(Li0.27Ti1.

Soft-chemical exfoliation of RbSrNb2O6F into homogeneously unilamellar oxyfluoride nanosheets.

Interlayer Rb(+) of the perovskite-type layered oxyfluoride RbSrNb(2)O(6)F was ion-exchanged with H(+), and the protonated phase was reacted with aqueous solution of tetrabutylammonium hydroxide to exfoliate it into nanosheets. The resulting nanosheet suspension exhibits Tyndall scattering of a laser beam, indicating its colloidal nature. Elemental composition of the nanosheet was estimated as Sr(0.

Exploration of mid-temperature alkali-metal-ion extraction route using PTFE (AEP): transformation of α-NaFeO2-type layered oxides into rutile-type binary oxides.

Alkali-metal-ion extraction reactions using poly(tetrafluoroethylene) (PTFE; AEP reactions) were performed on two kinds of α-NaFeO(2)-type layered compounds: Na(0.68)(Li(0.68/3)Ti(1-0.

A bona fide two-dimensional percolation model: an insight into the optimum photoactivator concentration in La Eu TaO nanosheets.

La-Eu solid solution nanosheets La Eu TaO have been synthesized, and their photoluminescence properties have been investigated. La Eu TaO nanosheets were prepared from layered perovskite compounds LiLa Eu TaO as the precursors by soft chemical exfoliation reactions. Both the precursors and the exfoliated nanosheets exhibit a decrease in intralayer lattice parameters as the Eu contents increase.

Engineered interfaces of artificial perovskite oxide superlattices via nanosheet deposition process.

Combining different materials into desired superlattice structures can produce new electronic states at the interface and the opportunity to create artificial materials with novel properties. Here we introduce a new, rather unexpected, and yet simple way to such a superlattice assembly of perovskite oxides: in the Dion-Jacobson phase, a model system of layered perovskites, high-quality bicolor perovskite superlattices (LaNb(2)O(7))(nL)(Ca(2)Nb(3)O(10))(nC) are successfully fabricated by a layer-by-layer assembly using two different perovskite nanosheets (LaNb(2)O(7) and Ca(2)Nb(3)O(10)) as a building block. The artificially fabricated (LaNb(2)O(7)/Ca(2)Nb(3)O(10)) superlattices are structurally unique, which is not feasible to create in the bulk form.

Synthesis of a solid solution series of layered Eu(x)Gd(1-x)(OH)2.5Cl0.5 x 0.9 H2O and its transformation into (Eu(x)Gd(1-x))2O3 with enhanced photoluminescence properties.

The synthesis of a series of new layered rare-earth hydroxide solid solutions and their transformation into (Eu(x)Gd(1-x))(2)O(3) crystallites are described. Highly crystalline platelets of Eu(x)Gd(1-x)(OH)(2.5)Cl(0.

An alkali-metal ion extracted layered compound as a template for a metastable phase synthesis in a low-temperature solid-state reaction: preparation of brookite from K0.8Ti1.73Li0.27O4.

We have designed a new approach to synthesize brookite, i.e., to extract alkali-metal ions from K(0.

Oriented monolayer film of Gd2O3:0.05 Eu crystallites: quasi-topotactic transformation of the hydroxide film and drastic enhancement of photoluminescence properties.

Caught on film: A semitransparent and intensely luminescent monolayer film of oriented Gd(2)O(3):0.05 Eu platelet crystallites is fabricated by annealing the precursor hydroxide film (see scheme). The photoluminescence properties of the as-transformed film are greatly improved over those of the hydroxide film, and are much more pronounced than those of the corresponding Gd(2)O(3):0.

Oriented films of layered rare-earth hydroxide crystallites self-assembled at the hexane/water interface.

Layered rare-earth hydroxide crystallites self-assembled at the hexane/water interface were transferred to various substrates to form a monolayer film, which exhibited photoluminescence properties and ion-exchange ability.

Chemistry of layered -metal pnictide oxides and their potential as candidates for new superconductors.

Layered -metal pnictide oxides are a unique class of compounds which consist of characteristic -metal pnictide layers and metal oxide layers. More than 100 of these layered compounds, including the recently discovered Fe-based superconducting pnictide oxides, can be classified into nine structure types. These structure types and the chemical and physical properties of the characteristic -metal pnictide layers and metal oxide layers of the layered -metal pnictide oxides are reviewed and discussed.

NaCl/KCl flux single crystal growth and crystal structure of the new quaternary mixed-metal pnictide: BaCuZn3As3.

Synthesis and crystal structure of a new compound, BaCuZn(3)As(3), are reported. Single crystals of BaCuZn(3)As(3) are synthesized via NaCl/KCl flux reaction in a sealed fused silica ampule. Its elemental composition has been determined to be Ba/Cu/Zn/As = 1.

Formation of a one-dimensional array of oxygen in a microporous metal-organic solid.

We report the direct observation of dioxygen molecules physisorbed in the nanochannels of a microporous copper coordination polymer by the MEM (maximum entropy method)/Rietveld method, using in situ high-resolution synchrotron x-ray powder diffraction measurements. The obtained MEM electron density revealed that van der Waals dimers of physisorbed O2 locate in the middle of nanochannels and form a one-dimensional ladder structure aligned to the host channel structure. The observed O-O stretching Raman band and magnetic susceptibilities are characteristic of the confined O2 molecules in one-dimensional nanochannels of CPL-1 (coordination polymer 1 with pillared layer structure).