This disclosure provides systems, methods, and apparatus related to inorganic halide perovskite nanowires. In one aspect, a first solution comprising cesium oleate or rubidium oleate in a first organic solvent is provided. A second solution comprising a lead halide and a surfactant in a second organic solvent is provided. The halide is selected from a group consisting of chlorine, bromine, and iodine. The first solution and the second solution are mixed. A reaction between the cesium oleate or the rubidium oleate and the lead halide forms a plurality of nanowires comprising an inorganic lead halide perovskite.

This disclosure provides systems, methods, and apparatus related to inorganic halide perovskite nanowires. In one aspect, a first solution comprising cesium oleate or rubidium oleate in a first organic solvent is provided. A second solution comprising a lead halide and a surfactant in a second organic solvent is provided. The halide is selected from a group consisting of chlorine, bromine, and iodine. The first solution and the second solution are mixed. A reaction between the cesium oleate or the rubidium oleate and the lead halide forms a plurality of nanowires comprising an inorganic lead halide perovskite.

The subject of the invention is the use, as catalyst support sublayer in a process for growing carbon nanotubes by chemical vapour deposition (CVD), of a multilayer stack formed of alternating layers of silica and of alumina, each of the layers having a thickness of less than or equal to 10 nm and consisting of one or more superposed atomic monolayer(s). It also relates to a multilayer structure comprising a substrate which has, on at least one of its faces, such a multilayer stack, and also to the use thereof for the growth of a mat of carbon nanotubes, which are in particular spinnable, by chemical vapour deposition, preferably hot-filament chemical vapour deposition.

A quantum dot having core-shell structure includes a core formed of ZnO.sub.zS.sub.1-z, and at least one shell covering the core, and formed of Al.sub.xGa.sub.yIn.sub.1-x-yN, wherein at least one of x, y, and z is not zero and is not one.

A quantum dot having core-shell structure includes a core formed of ZnO.sub.zS.sub.1-z, and at least one shell covering the core, and formed of Al.sub.xGa.sub.yIn.sub.1-x-yN, wherein at least one of x, y, and z is not zero and is not one.

Provided is a method for synthesizing TiO.sub.2 nanocrystal, comprising: adjusting the pH value of a colloidal suspension of tetratitanic acid nanosheet as a precursor to 5-13; and subjecting the precursor to a hydrothermal reaction to obtain the TiO.sub.2 nanocrystal. The TiO.sub.2 nanocrystal synthesized by the method is anatase-type, and the exposed crystal facet thereof is {010} crystal facet. The method has advantages of low cost, no pollution, simple synthesizing process, strong controllability, short production period and good reproducibility, and is suitable for industrial production.

A new set of branched nanowire or nanotree structures and their fabrication process. Some structures have one or more of the following distinctions from other branched nanowires: (1) the trunk and branch diameter and branching number density can be changed along the trunk's length; (2) the branch's azimuthal direction can be controlled along the trunk's length; (3) the branch's diameter can be modulated along its length; (4) the crystal orientation and branches of the ensemble of nanowires can be aligned on a non-epitaxially matched substrate. The structures are made by a geometrically controlled kinetic growth method.

A new set of branched nanowire or nanotree structures and their fabrication process. Some structures have one or more of the following distinctions from other branched nanowires: (1) the trunk and branch diameter and branching number density can be changed along the trunk's length; (2) the branch's azimuthal direction can be controlled along the trunk's length; (3) the branch's diameter can be modulated along its length; (4) the crystal orientation and branches of the ensemble of nanowires can be aligned on a non-epitaxially matched substrate. The structures are made by a geometrically controlled kinetic growth method.

The present disclosure is directed to compositions comprising at least one layer having first and second surfaces, each layer comprising: a substantially two-dimensional array of crystal cells, each crystal cell having an empirical formula of M′.sub.2M″nX.sub.n+1, such that each X is positioned within an octahedral array of M′ and M″; wherein M′ and M″ each comprise different Group 11113, WE, VB, or VIB metals; each X is C, N, or a combination thereof; n=1 or 2; and wherein the M′ atoms are substantially present as two-dimensional outer arrays of atoms within the two-dimensional array of crystal cells; the M″ atoms are substantially present as two-dimensional inner arrays of atoms within the two-dimensional array of crystal cells; and the two dimensional inner arrays of M″ atoms are sandwiched between the two-dimensional outer arrays of M′ atoms within the two-dimensional army of crystal cells.

The present disclosure is directed to compositions comprising at least one layer having first and second surfaces, each layer comprising: a substantially two-dimensional array of crystal cells, each crystal cell having an empirical formula of M′.sub.2M″nX.sub.n+1, such that each X is positioned within an octahedral array of M′ and M″; wherein M′ and M″ each comprise different Group 11113, WE, VB, or VIB metals; each X is C, N, or a combination thereof; n=1 or 2; and wherein the M′ atoms are substantially present as two-dimensional outer arrays of atoms within the two-dimensional array of crystal cells; the M″ atoms are substantially present as two-dimensional inner arrays of atoms within the two-dimensional array of crystal cells; and the two dimensional inner arrays of M″ atoms are sandwiched between the two-dimensional outer arrays of M′ atoms within the two-dimensional army of crystal cells.