Provided is a method for the preparation of a porous hollow shell WO.sub.3/WS.sub.2 nanomaterial, comprising: (1) adding a hexavalent tungsten salt to a sol A comprising mesocarbon microbeads, and stirring to obtain a sol B; (2) drying and grinding the sol B, and then heating a resulting powder at 200-500° C. for 0.5-2 hours to obtain a porous hollow shell WO.sub.3 nanocrystalline material; (3) placing the porous hollow shell WO.sub.3 nanocrystalline material obtained by Step 2 and a sulfur powder separately in a vacuum furnace, controlling such that a degree of vacuum is −0.01 to −0.1 MPa and a temperature is 200-500° C., and reacting for 0.5-3 hours to obtain a WO.sub.3/WS.sub.2 porous hollow shell nanocrystalline material. Also provided is a porous hollow shell WO.sub.3/WS.sub.2 nanocrystalline material obtained by the method.

The present invention relates to a method for preparing an aqueous or hydro-alcoholic colloidal solution of metal chalcogenide amorphous nanoparticles notably of the Cu.sub.2ZnSnS.sub.4 (CZTS) type and to the obtained colloidal solution. The present invention also relates to a method for manufacturing a film of large-grain crystallized semi-conducting metal chalcogenide film notably of CZTS obtained from an aqueous or hydro-alcoholic colloidal solution according to the invention, said film being useful as an absorption layer deposited on a substrate applied in a solid photovoltaic device.

The present invention relates to a method for preparing an aqueous or hydro-alcoholic colloidal solution of metal chalcogenide amorphous nanoparticles notably of the Cu.sub.2ZnSnS.sub.4 (CZTS) type and to the obtained colloidal solution.

The present invention also relates to a method for manufacturing a film of large-grain crystallized semi-conducting metal chalcogenide film notably of CZTS obtained from an aqueous or hydro-alcoholic colloidal solution according to the invention, said film being useful as an absorption layer deposited on a substrate applied in a solid photovoltaic device.

The present invention relates to a method for preparing an aqueous or hydro-alcoholic colloidal solution of metal chalcogenide amorphous nanoparticles notably of the Cu.sub.2ZnSnS.sub.4 (CZTS) type and to the obtained colloidal solution. The present invention also relates to a method for manufacturing a film of large-grain crystallized semi-conducting metal chalcogenide film notably of CZTS obtained from an aqueous or hydro-alcoholic colloidal solution according to the invention, said film being useful as an absorption layer deposited on a substrate applied in a solid photovoltaic device.

Provided is a method for the preparation of a porous hollow shell WO.sub.3/WS.sub.2 nanomaterial, comprising: (1) adding a hexavalent tungsten salt to a sol A comprising mesocarbon microbeads, and stirring to obtain a sol B; (2) drying and grinding the sol B, and then heating a resulting powder at 200-500 C. for 0.5-2 hours to obtain a porous hollow shell WO.sub.3 nanocrystalline material; (3) placing the porous hollow shell WO.sub.3 nanocrystalline material obtained by Step 2 and a sulfur powder separately in a vacuum furnace, controlling such that a degree of vacuum is 0.01 to 0.1 MPa and a temperature is 200-500 C., and reacting for 0.5-3 hours to obtain a WO.sub.3/WS.sub.2 porous hollow shell nanocrystalline material. Also provided is a porous hollow shell WO.sub.3/WS.sub.2 nanocrystalline material obtained by the method.

Aqueous and substantially crystalline iron oxide nanoparticle dispersions and processes for making them are disclosed. The nanoparticle size and size distribution width are advantageous for use in a fuel additive for catalytic reduction of soot combustion in diesel particulate filters. Nanoparticles of the aqueous colloid are transferred to a substantially non-polar liquid comprising a carboxylic acid and one or more low-polarity solvents. The transfer is achieved by mixing the aqueous and substantially non-polar materials, forming an emulsion, followed by a phase separation into a substantially metal-free remnant polar phase and a substantially non-polar organic colloid phase. A method for rapid and substantially complete transfer of non-agglomerated nanoparticles to the low polarity phase in the presence of an organic amine, and a rapid phase separation of the substantially non-polar colloid from a remnant aqueous phase, are provided.

The present invention relates to a method for preparing an aqueous or hydro-alcoholic colloidal solution of metal chalcogenide amorphous nanoparticles notably of the Cu.sub.2ZnSnS.sub.4 (CZTS) type and to the obtained colloidal solution.

The present invention also relates to a method for manufacturing a film of large-grain crystallized semi-conducting metal chalcogenide film notably of CZTS obtained from an aqueous or hydro-alcoholic colloidal solution according to the invention, said film being useful as an absorption layer deposited on a substrate applied in a solid photovoltaic device.