A solar-cell absorber layer for use in solar cells including tandem solar cells, is made of a metal-halide double perovskite material. The metal-halide double perovskite material has the formula A.sub.2BBX.sub.6, where A is an inorganic cation, an organic cation, or a mixture of organic and inorganic cations where B and B are metals, and where X is a halide or a mixture of halides. For example, A can be Cs, Rb, K, Ba, CH.sub.3NH.sub.3, (NH.sub.2).sub.2CH, or a mixture where B is Bi, Ag, Sn, In, Sb, Cu, Na, K, or Au of a predetermined oxidation state, and where B is Bi, Ag, Sn, In, Sb, Ga, Cu, or Au of various oxidation states, and where X is Br, I, Cl, F, or a mixture. One example of the metal-halide double perovskite material is Cs.sub.2BiAgBr.sub.6.

A thermoelectric material containing a dichalcogenide compound represented by Formula 1 and having low thermoelectric conductivity and high Seebeck coefficient:

R.sub.aT.sub.bX.sub.2-nY.sub.n (1)

wherein R is a rare earth element, T includes at least one element selected from the group consisting of Group 1 elements, Group 2 elements, and a transition metal, X includes at least one element selected from the group consisting of S, Se, and Te, Y is different from X and includes at least one element selected from the group consisting of S, Se, Te, P, As, Sb, Bi, C, Si, Ge, Sn, B, Al, Ga and In, a is greater than 0 and less than or equal to 1, b is greater than or equal to 0 and less than 1, and n is greater than or equal to 0 and less than 2.

A thermoelectric material containing a dichalcogenide compound represented by Formula 1 and having low thermoelectric conductivity and high Seebeck coefficient:
R.sub.aT.sub.bX.sub.2-nY.sub.n(1) wherein R is a rare earth element, T includes at least one element selected from the group consisting of Group 1 elements, Group 2 elements, and a transition metal, X includes at least one element selected from the group consisting of S, Se, and Te, Y is different from X and includes at least one element selected from the group consisting of S, Se, Te, P, As, Sb, Bi, C, Si, Ge, Sn, B, Al, Ga and In, a is greater than 0 and less than or equal to 1, b is greater than or equal to 0 and less than 1, and n is greater than or equal to 0 and less than 2.

Metal nanomaterials and nano structures may be formed via shearing force in the presence of a reactant.

The invention relates to a material comprising at least one compound having formula Bi.sub.1xM.sub.xAg.sub.1yM.sub.yOS.sub.1zM.sub.z, the methods for producing said material and the use thereof as a semiconductor, such as for photovoltaic or photochemical use and, in particular, for supplying a photocurrent. The invention further relates to photovoltaic devices using said compounds.

The Present teachings provide, in part, methods of separating two-dimensional nanomaterials by atomic layer thickness. In certain embodiments, the present teachings provide methods of generating graphene nanomaterials having a controlled number of atomic layer(s).

An embodiment can provide a material for a solid oxide fuel cell, a preparation method therefor, and an electrolyte and a fuel cell each comprising same, wherein the material has ion conductivity by doping of bismuth oxide with erbium (Er), yttrium (Y), and zirconium (Zr), and has excellent durability due to the absence of a reduction in ion conductivity or a phase transition to a rhombohedral-fluorite structure even when the fuel cell is operated at a temperature of 700 C. or lower for a long time.

An LLZ oxide may be a garnet-type oxide that contains Li, La, Zr and O as main constituent elements, and further contains substituent elements such as Zn in addition to the main constituent elements. The substituent elements may contain Bi, Nb, Hf and the like in addition to Zn. The LLZ-type oxide may be used, for example, as a solid electrolyte for an all-solid-state lithium ion secondary battery. The all-solid-state lithium ion secondary battery includes a positive electrode, a negative electrode, and a solid electrolyte layer that is disposed between the positive electrode and the negative electrode.

A 2D bismuth material, also called bismuthene, has a sandwich-like sheet structure with at least two outer layers formed by organic molecules containing sulphur atoms that form BiS bonds and at least one inner layer formed by a crystalline network of Bi(0) atoms. These materials are useful in electronic, optoelectronic, catalytic applications or in energy storage and transformation. Furthermore, a process produces this material from a bismuth salt that reacts with an amine and subsequently with a thiol by effect of the application of radiation and a subsequent reduction. This process has a colloidal approach to producing Bi(0) crystals based on a photocatalytic reduction of a soluble Bi(III) organometallic complex leading to the generation of the crystals.

The invention relates to a material comprising at least one compound having formula Bi.sub.1-xM.sub.xCu.sub.1-y-M.sub.yOS.sub.1-zM.sub.z, the methods for producing said material and the use thereof as a semiconductor, such as for photovoltaic or photochemical use and, in particular, for supplying a photocurrent. The invention further relates to photovoltaic devices using said compounds.