Electroconductive particle, visible light transmitting particle-dispersed electrical conductor and manufacturing method thereof, transparent electroconductive thin film and manufacturing method thereof, transparent electroconductive article that uses the same, and infrared-shielding article

Abstract

Provided is an infrared-shielding nanoparticle dispersion that has a property whereby visible light is adequately transmitted, and light in the near-infrared region is adequately shielded. The infrared-shielding nanoparticles include a plural aggregate of electroconductive particles composed of a tungsten oxide expressed by the general formula WyOz (where W is tungsten, O is oxygen, and 2.2≦z/y≦2.999), and/or a composite tungsten oxide expressed by the general formula MxWyOz (where M is one or more elements selected from H, alkali metals, alkaline-earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten; O is oxygen; 0.001≦x/y≦1.1; and 2.2≦z/y≦3.0).

1 . A visible light transmitting particle-dispersed electrical conductor, which is a plural aggregate of electroconductive particles composed of a tungsten oxide expressed by the general formula WyOz (where W is tungsten, O is oxygen, and 2.2≦z/y≦2.999), and/or a composite tungsten oxide expressed by the general formula MxWyOz (where M is one or more elements selected from H, alkali metals, alkaline-earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten; O is oxygen; 0.001≦x/y≦1.1; and 2.2≦z/y≦3.0), wherein
 the particle diameter is 1 nm or greater; 
 the particles have visible light transmitting characteristics; and 
 the pressed powder resistance of the particles measured under a pressure of 9.8 MPa is 1.0 Ω·cm or less. 
 
     
     
         2 . The visible light transmitting particle-dispersed electrical conductor of  claim 1 , wherein
 the electroconductive particles contain acicular crystals or are entirely composed of acicular crystals;   the ratio of the major and minor axes (major axis/minor axis) in the acicular crystals is 5 or greater; and   the length of the major axis ranges from 5 nm or greater to 10,000 μm or less.   
     
     
         3 . The visible light transmitting particle-dispersed electrical conductor of  claim 1 , wherein
 the electroconductive particles contain tabular crystals or are entirely composed of tabular crystals;   the thickness of the tabular crystals ranges from 1 nm or greater to 100 μm or less;   the maximum diagonal length of the tabular surfaces in the tabular crystals ranges from 5 nm or greater to 500 μm or less; and   the ratio of the maximum diagonal length and the thickness of the tabular crystals (maximum diagonal length/thickness) is 5 or greater.   
     
     
         4 . The visible light transmitting particle-dispersed electrical conductor of  claim 1 , wherein the electroconductive particles of the tungsten oxide include a Magneli phase having a composition ratio expressed by the general formula WyOz (where W is tungsten, O is oxygen, and 2.45≦z/y≦2.999). 
     
     
         5 . The visible light transmitting particle-dispersed electrical conductor of  claim 1 , wherein the crystal structure of the electroconductive particles of the composite tungsten oxide expressed by the formula MxWyOz has an amorphous structure, or a cubic, tetragonal, or hexagonal tungsten bronze structure. 
     
     
         6 . The visible light transmitting particle-dispersed electrical conductor of  claim 5 , wherein the added element M in the electroconductive particles of the composite tungsten oxide expressed by the formula MxWyOz is one or more elements selected from Cs, Rb, K, Tl, Ba, In, Li, Ca, Sr, Fe, and Sn. 
     
     
         7 . The visible light transmitting particle-dispersed electrical conductor of  claim 1 , wherein the shape of the electroconductive particles is one or more shapes selected from granular, acicular, or tabular. 
     
     
         8 . The visible light transmitting particle-dispersed electrical conductor of  claim 1 , wherein the visible light transmitting particle-dispersed electrical conductor is film-shaped. 
     
     
         9 . The visible light transmitting particle-dispersed electrical conductor of  claim 1 , wherein the visible light transmitting particle-dispersed electrical conductor contains a binder. 
     
     
         10 . The visible light transmitting particle-dispersed electrical conductor of  claim 9 , wherein the binder is a transparent resin or a transparent dielectric. 
     
     
         11 . Electroconductive particles that are used in the visible light transmitting particle-dispersed electrical conductor of  claim 1 . 
     
     
         12 . A visible-light-transmitting electroconductive article, wherein the visible light transmitting particle-dispersed electrical conductor of  claim 1  is formed on a base material. 
     
     
         13 . A method for manufacturing electroconductive particles that contain a composite tungsten oxide expressed by the general formula WyOz (where W is tungsten, O is oxygen, and 2.2≦z/y≦2.999), and/or a composite tungsten oxide expressed by the general formula MxWyOz (where M is one or more elements selected from H, alkali metals, alkaline-earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten; O is oxygen; 0.001≦x/y≦1.1; and 2.2≦z/y≦3.0), wherein
 the tungsten compound as a starting material of the electroconductive particles is heat treated in a reducing gas and/or an inert gas atmosphere to manufacture the electroconductive particles. 
 
     
     
         14 . The method for manufacturing the electroconductive particles of  claim 13 , wherein the heat treatment includes heat treating a tungsten compound, which is a starting material of the electroconductive particles, at a temperature ranging from 100° C. or greater to 850° C. or less in an atmosphere of a reducing gas, and subsequently heat treating the tungsten compound as required at a temperature ranging from 550° C. or greater to 1,200° C. or less in an atmosphere of an inert gas. 
     
     
         15 . The method for manufacturing the electroconductive particles of  claim 13 , wherein a tungsten compound as a starting material of the electroconductive particles is one or more materials selected from tungsten trioxide; tungsten dioxide; a hydrate of tungsten oxide; tungsten hexachloride; ammonium tungstate; tungstic acid; a hydrate of tungsten oxide obtained by dissolving tungsten hexachloride in an alcohol and then drying the solution; a hydrate of tungsten oxide obtained by dissolving tungsten hexachloride in an alcohol, adding water to the solution to form a precipitate, and drying the precipitate; a tungsten compound obtained by drying an aqueous solution of ammonium tungstate; and a metal tungsten powder. 
     
     
         16 . The method for manufacturing the electroconductive particles  claim 13 , wherein
 one or more powders selected from a powder in which a tungsten compound, which is a starting material of the electroconductive particles of  claim 15 , and an element or compound containing an element M (where M is one or more elements selected from H, alkali metals, alkaline-earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I) are mixed; and   a powder, obtained by mixing a solution or liquid dispersion of the tungsten compound and a solution or liquid dispersion of the compound containing the element M and drying the solution, is used as the tungsten compound that is the starting material of the electroconductive particles.   
     
     
         17 . A transparent electroconductive film composed of a tungsten oxide expressed by the general formula WyOz (where W is tungsten, O is oxygen, and 2.2≦z/y≦2.999), and/or a composite tungsten oxide expressed by the general formula MxWyOz (where M is one or more elements selected from H, alkali metals, alkaline-earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, TI, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten; O is oxygen; 0.001≦x/y≦1.1; and 2.2≦z/y≦3.0), wherein
 the maximum transmittance of the film in the region of 400 nm or greater to 780 nm or less ranges from 10% or greater to less than 92%; and 
 the surface resistance of the film is 1.0×10 10  Ω/square or less. 
 
     
     
         18 . The transparent electroconductive film of  claim 17 , wherein
 said element M includes one or more elements selected from Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn; and   a composite oxide expressed by said general formula MxWyOz has a hexagonal crystal structure.   
     
     
         19 . The transparent electroconductive film of  claim 17 , wherein said tungsten oxide has a Magneli phase having a composition ratio expressed by the general formula WyOz (where W is tungsten, O is oxygen, and 2.45≦z/y≦2.999). 
     
     
         20 . The transparent electroconductive film of  claim 17 , wherein the composite tungsten oxide expressed by said general formula MxWyOz has an amorphous structure, or one or more structures selected from cubic, tetragonal, and hexagonal tungsten bronze structures. 
     
     
         21 . The transparent electroconductive film of  claim 20 , wherein the added element M in the hexagonal composite tungsten oxide expressed by said formula MxWyOz is one or more elements selected from Cs, Rb, K, Tl, Ba, In, Li, Ca, Sr, Fe, and Sn. 
     
     
         22 . A transparent electroconductive article, wherein said transparent electroconductive film of  claim 17  is formed on a base material. 
     
     
         23 . The transparent electroconductive article of  claim 22 , wherein the thickness of the transparent electroconductive film ranges from 1 nm or greater to 5,000 nm or less. 
     
     
         24 . An infrared-shielding article, wherein the transparent electroconductive film of  claim 17  is formed on a base material and has an infrared-shielding function. 
     
     
         25 . A method for manufacturing a transparent electroconductive film composed of a tungsten oxide expressed by the general formula WyOz (where W is tungsten, O is oxygen, and 2.2≦z/y≦2.999), and/or a composite tungsten oxide expressed by the general formula MxWyOz (where M is one or more elements selected from H, alkali metals, alkaline-earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten; O is oxygen; 0.001≦x/y≦1; and 2.2≦z/y≦3.0), and/or a composite oxide expressed by the general formula M E A G W (1-G) O J  (where the element A is one or more elements selected from Mo, Nb, Ta, Mn, V, Re, Pt, Pd, and Ti; 0<E≦1.2; 0<G≦1; and 2≦J≦3), wherein
 a solution composed of said tungsten oxide, and/or the composite tungsten oxide, and/or the starting material compound of the composite oxide is applied to a base material and heat treated in an atmosphere of a reducing gas and/or an inert gas to manufacture said transparent electroconductive film. 
 
     
     
         26 . The method for manufacturing a transparent electroconductive film of  claim 25 , wherein
 a surfactant is added to the solution composed of said tungsten oxide, and/or the composite tungsten oxide, and/or the starting material compound of the composite oxide; and   the solution is then applied to a base material.   
     
     
         27 . The method for manufacturing a transparent electroconductive film of  claim 25 , wherein the solution composed of said tungsten oxide, and/or the composite tungsten oxide, and/or the starting material compound of the composite oxide is a solution obtained by dissolving tungsten hexachloride in an alcohol when tungsten is used, and/or is an aqueous solution of ammonium tungstate. 
     
     
         28 . The method for manufacturing a transparent electroconductive film of  claim 25 , wherein a solution, obtained by dissolving and mixing an aqueous solution of ammonium tungstate and/or a solution obtained by dissolving tungsten hexachloride in alcohol according to the claim  30 , and a compound having the element M (where M is one or more elements selected from H, He, alkali metals, alkaline-earth metals, rare earth elements, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I), is applied to a base material directly or after a surfactant has been added. 
     
     
         29 . The method for manufacturing a transparent electroconductive film of  claim 25 , wherein said heat treatment is performed at a temperature ranging from 100° C. or greater to 800° C. or less in an atmosphere of a reducing gas, and is subsequently performed as required at a temperature ranging from 550° C. or greater to 1,200° C. or less in an atmosphere of an inert gas.