# US 8,814,979 B2 · Methods for the production of silver nanowires > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,814,979 B2 - Document ID: US8814979B2 - Status: Granted - Kind: B2 - Application number: 13/053,176 - Filed: 2011-03-21 - Published: 2011-08-04 - Granted: 2014-08-26 - Earliest claimed: 2008-02-02 - Assignees: Seashell Technology, LLC - Applicants: Yuliang Wang - Inventors: Yuliang Wang - Web page: https://patentgrep.com/patent/US8814979B2 ## CPC - B22F 9/24: starting from liquid metal compounds, e.g. solutions - B22F 1/062: Fibrous particles - B22F 1/07: Metallic powder characterised by particles having a nanoscale microstructure (nanosized particles B22F1/054) - C22B 11/04: {by wet processes (extraction of metal compounds by leaching in organic solutions C22B3/16; treatment or purification of solutions by liquid-liquid extraction C22B3/26)} - C22C 5/06: Alloys based on silver - C30B 7/14: the crystallising materials being formed by chemical reactions in the solution - C30B 29/02: Elements - C30B 29/605: {Products containing multiple oriented crystallites, e.g. columnar crystallites} - B22F 2301/255: Silver or gold - B22F 2998/00: Supplementary information concerning processes or compositions relating to powder metallurgy - Y10S 977/896: Chemical synthesis, e.g. chemical bonding or breaking - B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER - C22B: PRODUCTION AND REFINING OF METALS (electrolytic C25); PRETREATMENT OF RAW MATERIALS - C22C: ALLOYS (treatment of alloys C21D, C22F) - C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract Embodiments of the present invention are directed to novel methods for the solution-based production of silver nanowires by adaptation of the polyol process. Some embodiments of the present invention can be practiced at lower temperature and/or at higher concentration than previously described methods. In some embodiments reactants are added in solid form rather than in solution. In some embodiments, an acid compound is added to the reaction. ## Claims ### Claim 1 A method for the production of silver nanowires comprising reacting: i) at least one polyol; ii) at least one silver solution comprising at least one silver compound capable of producing silver metal when reduced; and iii) at least one organic protective agent (OPA); as reactants in a reaction at a reaction temperature and under conditions that produce silver nanowires wherein the molar concentration of the silver compound in the silver solution is in the range of about 0.3 molar to about 3.0 molar, wherein the nanowires have an aspect ratio (length/diameter) of at least 10. ### Claim 2 (depends on 1) The method of claim 1, wherein the polyol is ethylene glycol, glycerol, glucose, diethylene glycol, tri-ethylene glycol, a propylene glycol, a butanediol, a dipropylene glycol or a polyethylene glycol. ### Claim 3 (depends on 1) The method of claim 1, wherein the silver compound is silver nitrate, silver nitrite, silver oxide, silver fluoride, silver hydrogen fluoride, silver carbonate, silver oxalate, silver azide, silver tetrafluoroborate, silver acetate, silver propionate, silver butanoate, silver ethylbutanoate or silver pivalate. ### Claim 4 (depends on 1) The method of claim 1, wherein the organic protective agent (OPA) is poly(vinyl pyrrolidone) (PVP), poly(vinyl alcohol) (PVA), sodium dodecyl sulfate (SDS), laurylamine or hydroxypropyl cellulose. ### Claim 5 (depends on 1) The method of claim 1, wherein the product solution comprises at least 20 weight percent (20 wgt %) silver nanowires. ### Claim 6 (depends on 1) The method of claim 1, wherein the silver nanowires have an aspect ratio of at least 200. ### Claim 7 (depends on 1) The method of claim 1, wherein the organic protective agent (OPA) is added to the reaction in solid form. ### Claim 8 (depends on 1) The method of claim 1, wherein the silver compound is reacted as a silver solution comprising the silver compound in a first portion of the polyol and the organic protective agent is reacted as an OPA solution comprising the organic protective agent in a second portion of the polyol. ### Claim 9 (depends on 8) The method of claim 8, wherein the silver solution and the OPA solution are mixed for reaction with a third portion of the polyol in a reaction vessel. ### Claim 10 (depends on 1) The method of claim 1, further comprising reacting at least one acid compound. ### Claim 11 (depends on 1) The method of claim 1, wherein the reaction produces bulk silver nanowire product having a length weighted average of at least 10 μm. ### Claim 12 (depends on 1) The method of claim 1, wherein the reaction produces bulk silver nanowire product having an aspect ratio weighted average that is at least 125. ### Claim 13 (depends on 1) The method of claim 1, wherein the silver nanowires have an aspect ratio of at least 500. ### Claim 14 (depends on 1) The method of claim 1, wherein the silver nanowires have an aspect ratio of at least 750. ### Claim 15 (depends on 1) The method of claim 1, wherein said product solution comprises nanowires with a weighted average length of 25-30 μm. ### Claim 16 A method for the production of silver nanowires comprising: i) mixing as reactants for a reaction: a) at least one silver solution comprising at least one silver compound capable of producing silver metal when reduced; b) at least one polyol; and c) at least one organic protective agent to produce a mixture; and ii) reacting said mixture at a reaction temperature and under conditions that produce a product solution comprising silver nanowires; wherein, the molar concentration of the silver compound in the silver solution is in the range of about 0.3 molar to about 3.0 molar, and the nanowires have an aspect ratio (length/diameter) of at least 10. ### Claim 17 (depends on 16) The method of claim 16, wherein the polyol is ethylene glycol, glycerol, glucose, diethylene glycol, tri-ethylene glycol, a propylene glycol, a butanediol, a dipropylene glycol or a polyethylene glycol. ### Claim 18 (depends on 16) The method of claim 16, wherein the silver compound is silver nitrate, silver nitrite, silver oxide, silver fluoride, silver hydrogen fluoride, silver carbonate, silver oxalate, silver azide, silver tetrafluoroborate, silver acetate, silver propionate, silver butanoate, silver ethylbutanoate or silver pivalate. ### Claim 19 (depends on 16) The method of claim 16, wherein the organic protective agent (OPA) is poly(vinyl pyrrolidone) (PVP), poly(vinyl alcohol) (PVA), sodium dodecyl sulfate (SDS), laurylamine or hydroxypropyl cellulose.