Method for producing nanoparticles of transition metals

A method of forming nanoparticles comprising:

• forming a metal precursor solution as a complex of a transition metal at a first temperature,
• forming a surfactant solution at a second temperature higher than said first temperature, said surfactant solution comprises a combination of an organic stabilizer and a phosphine to protect said nanonarticles, and said organic stabilizer being a long chain organic compound of the form R—X, where R is a member selected from the group consisting of 1) a hydrocarbon chain in straight or branched formation. said hydrocarbon chain comprising 6 to 22 carbon atoms, and 2) a fluorocarbon chain in straight or branched formation, said fluorocarbon chain comprising 6 to 22 carbon atoms, and, where X is selected from the group consisting of carboxylic acid, phosphoric acid, phosphinic acid. sulfonic acid, sulfinic acids, and thiol;
• introducing said metal precursor solution to said surfactant solution, to form a mixture, wherein said forming the surfactant solution and said introducing is performed in an inert atmosphere without the presence of oxygen;
• adding a flocculent to said mixture to cause nanoparticles to precipitate out of solution without permanent agglomeration;
• and
• adding a hydrocarbon solvent for one of redispersing and repeptizing said nanoparticles.

A method of forming nanoparticles comprising:

• forming a metal precursor solution at a first temperature, said metal precursor solution containing a surfactant solution comprises a combination of an organic stabilizer and a phosphine to protect said nanoparticles, and said organic stabilizer being, a long chain organic compound of the form R—X, where R is a member selected from the group consisting of 1) a hydrocarbon chain in straight or branched formation, said hydrocarbon chain comprising 6 to 22 carbon atoms, and 2) a fluorocarbon chain in straight or branched formation, said fluorocarbon chain comprising 6 to 22 carbon atoms, and where X is selected from the group consisting of carboxylic acid, phosphoric acid, phosphinic acid, sulfonic acid, sulfinic acids, and thiol;
• introducing a reducing agent at a second temperature into said metal precursor solution, wherein said forming and said introducing is performed with the exclusion of oxygen in an inert atmosphere;
• adding a flocculent to cause nanoparticles to precipitate out of solution without permanent agglomeration;
• and
• adding a hydrocarbon solvent for one of redispersing and repeptizing said nanoparticles.

A method of forming nanoparticles, including:

• forming a metal salt precursor solution containing a surfactant in a non-reactive solvent, said surfactant solution comprises a combination of an organic stabilizer and a phosphine to protect said nanoparticles, and said organic stabilizer being a long chain organic comnound of the form R—X, where R is a member selected from the group consisting of 1) a hydrocarbon chain in straight or branched formation, said hydrocarbon chain comprising 6 to 22 carbon atoms, and 2) a fluorocarbon chain in straight or branched formation, said fluorocarbon chain comprising 6 to 22 carbon atoms, and where X is selected from the group consisting of carboxmlic acid, phosphoric acid, phosphinic acid, sulfonic acid, sulfinic acids, and thiol;
• injecting an agent into the solution to reduce the metal salt in situ to produce colloidal metal particles, wherein said forming and iniecting is performed in an inert atmosphere with the exclusion of oxygen;
• adding a flocculent to cause nanoparticles to precipitate out of solution without permanent agglomeration and separating by-products of synthesis which remain in solution;
• and
• adding a hydrocarbon solvent to the nanoparticles precipitated out, to one of redisperse and repeptize the nanoparticles.

A method of forming nanoparticles, comprising:

• forming a metal precursor solution from a transition metal;
• introducing said metal precursor solution to a surfactant solution, wherein said forming and introducing is performed in an inert atmosphere with the exclusion of oxygen;
• adding a flocculent to cause nanoparticles to precipitate out of solution without permanent agglomeration;
• and
• adding a hydrocarbon solvent for one of redispersing and repeptizing said nanoparticles,
• wherein said nanoparticles comprise cobalt-based nanoparticles, and a combination of carboxylic acid and trialkylphosphine are used to protect said cobalt-based nanoparticles, and
• wherein a particle size is controlled by changing a ratio of said acid and said trialkylphosphine, the acid being RCOOH with R equal to one of C12H24, C17H34, and C21H42 and the trialkylphosphine being organophosphine with R being one of Phenyl, C2H5, C4H9, and C8H17.

A method of forming nanoparticles, comprising:

• forming a metal precursor solution at a first temperature approximately 240° C.;
• introducing a reducing agent at a second temperature less than approximately 240° C. into said metal precursor solution, wherein said forming and said introducing is performed with the exclusion of oxygen in an inert atmosphere;
• adding a flocculent to cause nanoparticles to precipitate out of solution without permanent agglomeration;
• and
• adding a hydrocarbon solvent for one of redispersing and repeptizing said nanoparticles,
• wherein said nanoparticles comprise cobalt-based nanoparticles, and a combination of carboxylic acid and trialkylphosphine are used to protect said cobalt-based nanoparticles, and
• wherein a particle size is controlled by changing a ratio of said acid and said trialkylphosphine, the acid being RCOOH with R equal to one of C12H24, C17H34, and C21H42 and the trialkylphosphine being organophosphine with R being one of Phenyl, C2H5, C4H9, and C8H17.

A method of forming nanoparticles, comprising:

• forming a metal salt precursor solution containing a surfactant comprises at least one of a tertiary alkylphosphine and oleic acid;
• injecting an agent into the solution to reduce the metal salt in situ to produce colloidal metal particles, wherein said forming and injecting is performed in an inert atmosphere with the exclusion of oxygen;
• adding a flocculent to cause nanoparticles to precipitate out of solution without permanent agglomeration and separating by-products of synthesis which remain in solution;
• and
• adding a hydrocarbon solvent to the nanoparticles precipitated out, to one of redisperse and repeptize the nanoparticles.

A method of forming nanoparticles, comprising:

• forming a metal precursor solution from a transition metal;
• introducing said metal precursor solution to a surfactant solution, wherein said forming and introducing performed in an inert atmosphere with the exclusion of oxygen, said surfactant solution comprises a combination of a nonionic surfactant and an ionic surfactant to protect said nanoparticles;
• adding a flocculent to cause nanoparticles to precipitate out of solution without permanent agglomeration;
• and
• adding a hydrocarbon solvent for one of redispersing and repeptizing said nanoparticles,
• wherein said nonionic surfactant is a phosphine and said ionic surfactant is an organic stabilizer being a long chain organic compound of the form R—X, where R is a member selected from the group consisting of 1) a hydrocarbon chain in straight or branched formation, said hydrocarbon chan comprising 6 to 22 carbon atoms, and 2) a fluorocarbon chain in straight or branched formation, said fluorocarbon chain comprising 6 to 22 carbon atoms, and where X is selected from the group consisting of carboxylic acid, phosphoric acid, phosphinic acid, sulfonic acid, sulfinic acids, and thiol.