Disclosed are a single-source precursor for synthesizing metal chalcogenide nanoparticles for producing a light absorption layer of solar cells comprising a Group VI element linked as a ligand to any one metal selected from the group consisting of copper (Cu), zinc (Zn) and tin (Sn), metal chalcogenide nanoparticles produced by heat-treating at least one type of the single-source precursor, a method of preparing the same, a thin film produced using the same and a method of producing the thin film.

An object of the present invention is to provide a novel sulfur-based positive electrode active material for a lithium-ion secondary battery which is excellent in cyclability and can largely improve a charging and discharging capacity, a positive electrode comprising the positive electrode active material and a lithium-ion secondary battery made using the positive electrode. The sulfur-based positive electrode active material is obtainable by subjecting a starting material comprising a polymer, sulfur and an organometallic compound dispersed in a form of fine particles to heat-treatment under a non-oxidizing atmosphere, wherein the particles of metallic sulfide resulting from sulfurization of the organometallic compound are dispersed in the heat-treated material, and particle size of the metallic sulfide particles is not less than 10 nm and less than 100 nm.

An object of the present invention is to provide a novel sulfur-based positive electrode active material for a lithium-ion secondary battery which is excellent in cyclability and can largely improve a charging and discharging capacity, a positive electrode comprising the positive electrode active material and a lithium-ion secondary battery made using the positive electrode. The sulfur-based positive electrode active material is obtainable by subjecting a starting material comprising a polymer, sulfur and an organometallic compound dispersed in a form of fine particles to heat-treatment under a non-oxidizing atmosphere, wherein the particles of metallic sulfide resulting from sulfurization of the organometallic compound are dispersed in the heat-treated material, and particle size of the metallic sulfide particles is not less than 10 nm and less than 100 nm.

A method is provided for producing an article which is transparent to IR wavelength in the region of 4 μm to 9 μm. The method includes the steps of (a) Producing ultra-fine powders of ZnS, (b) followed by pretreatment of the ultra-fine powders under reduced gas conditions including H2, H2S, N2, Ar and mixtures there of (c) followed by vacuum (3×10.sup.−6 torr) treatment to remove oxygen and sulfates adsorbed to the surface disposing a plurality of nano-particles on a substrate, wherein said nanoparticles comprise ZnS with ultra-high purity of cubic phase; (b) subjecting the nano-particles to spark plasma sintering thereby producing a sintered ZnS product with IR transmission reaching 75% in the wavelength range of 4 μm to 9 μm.

A method is provided for producing an article which is transparent to IR wavelength in the region of 4 μm to 9 μm. The method includes the steps of (a) Producing ultra-fine powders of ZnS, (b) followed by pretreatment of the ultra-fine powders under reduced gas conditions including H2, H2S, N2, Ar and mixtures there of (c) followed by vacuum (3×10.sup.−6 torr) treatment to remove oxygen and sulfates adsorbed to the surface disposing a plurality of nano-particles on a substrate, wherein said nanoparticles comprise ZnS with ultra-high purity of cubic phase; (b) subjecting the nano-particles to spark plasma sintering thereby producing a sintered ZnS product with IR transmission reaching 75% in the wavelength range of 4 μm to 9 μm.

Described are Zn.sub.xCd.sub.1-xS.sub.ySe.sub.1-y/ZnS.sub.zSe.sub.1-z core/shell nanocrystals, CdTe/CdS/ZnS core/shell/shell nanocrystals, optionally doped Zn(S,Se,Te) nano- and quantum wires, and SnS quantum sheets or ribbons, methods for making the same, and their use in biomedical and photonic applications, such as sensors for analytes in cells and preparation of field effect transistors.

Described are Zn.sub.xCd.sub.1-xS.sub.ySe.sub.1-y/ZnS.sub.zSe.sub.1-z core/shell nanocrystals, CdTe/CdS/ZnS core/shell/shell nanocrystals, optionally doped Zn(S,Se,Te) nano- and quantum wires, and SnS quantum sheets or ribbons, methods for making the same, and their use in biomedical and photonic applications, such as sensors for analytes in cells and preparation of field effect transistors.

There is provided a method of forming a porous particle comprising an electrically conductive continuous shell encapsulating a core, said core comprising an elemental compound that reversibly reduces in the presence of a cation and oxidizes in the absence of said cation, said method comprising the steps of: a) encapsulating an elemental compound precursor with said electrically conductive shell; b) reacting said elemental compound precursor with an oxidation agent to oxidise said elemental compound precursor to form said elemental compound, thereby forming said electrically conductive shell encapsulating said core comprising said elemental compound.

There is provided a method of forming a porous particle comprising an electrically conductive continuous shell encapsulating a core, said core comprising an elemental compound that reversibly reduces in the presence of a cation and oxidizes in the absence of said cation, said method comprising the steps of: a) encapsulating an elemental compound precursor with said electrically conductive shell; b) reacting said elemental compound precursor with an oxidation agent to oxidise said elemental compound precursor to form said elemental compound, thereby forming said electrically conductive shell encapsulating said core comprising said elemental compound.

The invention is directed to a method for producing non-oxide semiconductor nanoparticles, the method comprising: (a) subjecting a combination of reaction components to conditions conducive to microbially-mediated formation of non-oxide semiconductor nanoparticles, wherein said combination of reaction components comprises i) anaerobic microbes, ii) a culture medium suitable for sustaining said anaerobic microbes, iii) a metal component comprising at least one type of metal ion, iv) a non-metal component comprising at least one non-metal selected from the group consisting of S, Se, Te, and As, and v) one or more electron donors that provide donatable electrons to said anaerobic microbes during consumption of the electron donor by said anaerobic microbes; and (b) isolating said non-oxide semiconductor nanoparticles, which contain at least one of said metal ions and at least one of said non-metals. The invention is also directed to non-oxide semiconductor nanoparticle compositions produced as above and having distinctive properties.