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US 7,252,749 B2Granted
Deposition method for nanostructure materials
AssigneeThe University of North Carolina at Chapel Hill
InventorsOtto Z. Zhou, Bo Gao, Guozhen Yue, Soojin Oh
Life of this patent
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Abstract
A method for depositing a coating of a nanostructure material onto a substrate includes: (1) forming a solution or suspension of containing the nanostructure material; (2) selectively adding “chargers” to the solution; (3) immersing electrodes in the solution, the substrate upon which the nanostructure material is to be deposited acting as one of the electrodes; (4) applying a direct and/or alternating current electrical field between the two electrodes for a certain period of time thereby causing the nanostructure materials in the solution to migrate toward and attach themselves to the substrate electrode; and (5) subsequent optional processing of the coated substrate.
Claims106
A method of depositing a composite film with at least one component being a nanostructured material onto a substrate, the method comprising:
- (i) forming a suspension of the material in a liquid medium, the nanostructured material comprising at least one of nanotubes and nanowires;
- (ii) adding small particles to the suspension to promote adhesion of the nanostructured material to the substrate, wherein the small particles comprise a metal selected from the group consisting of iron, lead, and cobalt;
- (iii) selectively adding a charger to the liquid medium;
- (iv) immersing electrodes in the suspension, wherein at least one of the electrodes comprises the substrate;
- and
- (v) applying a direct or alternating current to the immersed electrodes thereby creating an electrical field between the electrodes;
- wherein the nanostructured material and the small particles are co-deposited on the substrate to form a composite layer, the composite layer having an intimate mix of the carbon nanotubes and the small particles, and wherein the composite layer has an emission current density greater than 1 A/cm2.
4 more elements
A method of depositing a composite layer with at least one component being carbon nanotubes onto a substrate, the method comprising:
- (i) forming a suspension containing at least the carbon nanotubes and an adhesion promoting material in a liquid medium, the adhesion promoting material further comprising a carbon-dissolving material selected from the group consisting of nickel, iron, cobalt and manganese;
- (ii) selectively adding a charger to the liquid medium;
- (iii) immersing electrodes in the suspension, wherein at least one of the electrodes comprises the substrate;
- and
- (iv) applying a direct or alternating current to the immersed electrodes thereby creating an electrical field between the electrodes;
- wherein the carbon nanotubes and the adhesion promoting material co-deposit on the substrate to form the composite layer, the composite layer having an intimate mix of the carbon nanotubes and the adhesion-promoting material.
3 more elements
A method of depositing a composite layer with at least one component being carbon nanotubes onto a substrate, the method comprising:
- (i) forming a suspension containing at least the carbon nanotubes and an adhesion promoting material in a liquid medium, the adhesion promoting material further comprising a carbide-forming material selected from the group consisting of tantalum, niobium, vanadium, and hafnium;
- (ii) selectively adding a charger to the liquid medium;
- (iii) immersing electrodes in the suspension, wherein at least one of the electrodes comprises the substrate;
- and
- (iv) applying a direct or alternating current to the immersed electrodes thereby creating an electrical field between the electrodes;
- wherein the carbon nanotubes and the adhesion promoting material co-deposit on the substrate to form the composite layer, the composite layer having an intimate mix of the carbon nanotubes and the adhesion-promoting material.
3 more elements
A method of depositing a composite layer with at least one component being carbon nanotubes onto a substrate, the method comprising:
- (i) forming a suspension containing at least the carbon nanotubes and an adhesion promoting material in a liquid medium, the adhesion promoting material further comprising a binder selected from the group consisting of poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) and poly(vinylidene fluoride);
- (ii) selectively adding a charger to the liquid medium;
- (iii) immersing electrodes in the suspension, wherein at least one of the electrodes comprises the substrate;
- and
- (iv) applying a direct or alternating current to the immersed electrodes thereby creating an electrical field between the electrodes;
- wherein the carbon nanotubes and the adhesion promoting material co-deposit on the substrate to form the composite layer, the composite layer having an intimate mix of the carbon nanotubes and the adhesion-promoting material.
3 more elements
A method of depositing a layer with at least one component being carbon nanotubes onto a substrate, the method comprising:
- (i) forming a suspension containing at least the carbon nanotubes;
- (ii) selectively adding a charger to the liquid medium;
- (iii) immersing electrodes in the suspension, wherein at least one of the electrodes comprises the substrate;
- and
- (iv) applying a direct or alternating current to the immersed electrodes thereby creating an electrical field between the electrodes;
- (v) removing the electrodes from the suspension;
- and
- (vi) annealing the coated substrate in a two-step annealing process, said two-step annealing process comprising heating the coated substrate to a first temperature for a first selected period of time, then heating the coated substrate to a second temperature for a second selected period of time;
- wherein the carbon nanotubes deposit on the substrate to form the layer.
6 more elements
A method of depositing a layer with at least one component being carbon nanotubes onto a substrate, the method comprising:
- (i) forming a suspension containing at least the carbon nanotubes in a liquid medium;
- (ii) selectively adding a charger to the liquid medium;
- (iii) immersing electrodes in the suspension, wherein at least one of the electrodes comprises the substrate, wherein the substrate is pre-coated with at least one layer of an adhesion-promoting metal selected from the group consisting of titanium, iron, lead, cobalt, nickel, tantalum, tungsten, niobium, zirconium, vanadium, and hafnium;
- and
- (iv) applying a direct or alternating current to the immersed electrodes thereby creating an electrical field between the electrodes;
- wherein the carbon nanotubes deposit on the substrate to form the composite layer having an intimate mix of the carbon nanotubes and the adhesion promoting metal, and wherein the composite layer has an emission current density greater than 1 A/cm2.
3 more elements
A method of depositing a composite layer with at least one component being carbon nanotubes onto a substrate, the method comprising:
- (i) forming a suspension containing at least the carbon nanotubes and an adhesion promoting material in a liquid medium, wherein the adhesion promoting material is selected from the group consisting of poly(vinyl butyral-co vinyl alcohol-co-vinyl acetate), poly(vinylidene fluoride), titanium, iron, lead, cobalt, nickel, tantalum, tungsten, niobium, zirconium, vanadium, chromium, hafnium, manganese, silicon, and molybdenum, said liquid medium comprising dimethyl formamide (DMF);
- (ii) selectively adding a charger to the liquid medium;
- (iii) immersing electrodes in the suspension, wherein at least one of the electrodes comprises the substrate;
- and
- (iv) applying a direct or alternating current to the immersed electrodes thereby creating an electrical field between the electrodes;
- wherein the carbon nanotubes and the adhesion promoting material co-deposit on the substrate to form the composite layer, the composite layer having an intimate mix of the carbon nanotubes and the adhesion-promoting material, and wherein the composite layer has an emission current density greater than 1 A/cm2.
3 more elements
A method of depositing a composite film with at least one component being a nanostructured material onto a substrate, the method comprising:
- (i) forming a suspension of the material in a liquid medium, the nanostructured material comprising at least one of nanotubes and nanowires;
- (ii) adding small particles to the suspension to promote adhesion of the nanostructured material to the substrate, wherein the small particles comprise a metal selected from the group consisting of iron, lead, and cobalt;
- (iii) selectively adding a charger to the liquid medium;
- (iv) immersing electrodes in the suspension, wherein at least one of the electrodes comprises the substrate;
- and
- (v) applying a direct or alternating current to the immersed electrodes thereby creating an electrical field between the electrodes;
- wherein the nanostructured material and the small particles are co-deposited on the substrate to form a composite layer, and further wherein the composite layer;
- (a) comprises an intimate mix of the carbon nanotubes and the small particles;
- (b) produces an emission current density greater than 1 A/cm2;
- (c) has a threshold field for emission of less than 1.5 V/micrometer;
- and
- (d) produces a total emission current greater than 10 mA over a 6 2 mm area, a pulsed emission current having a pulse frequency higher than 100 KHz, and a total pulsed current measured over a 6 mm2 area of greater than 10 mA at between 10 and 12 V/micrometer for at least 1,000 pulses.
9 more elements
A method of depositing a multilayer coating onto a substrate, the method comprising:
- (i) forming a plurality of stable liquid suspensions, wherein each suspension comprises carbon nanotubes and at least one or more component selected from a polymer and metal particles, wherein the polymer is selected from the group consisting of poly(vinyl butyral-co vinyl alcohol-co-vinyl acetate) and poly(vinylidene fluoride), and the metal particles are selected from the group consisting of titanium, iron, lead, cobalt, nickel, tantalum, tungsten, niobium, zirconium, vanadium, chromium, hafnium, manganese, silicon, and molybdenum;
- (ii) selectively adding a charger to each of the plurality of stable liquid suspensions;
- (iii) immersing electrodes into one of the plurality of stable liquid suspensions, wherein at least one of the electrodes comprises the substrate;
- (iv) applying a direct or alternating current to the immersed electrodes thereby creating an electrical field between the electrodes, wherein the carbon nanotubes and the at least one other component migrate toward and attach to the substrate to form a composite layer, wherein the applying is for a period of time until a desired thickness of the composite layer is reached;
- (v) removing the electrodes from the stable liquid suspension;
- (vi) immersing the electrodes into another of the plurality of stable liquid suspensions and repeating steps (iv) and (v);
- and
- (vii) repeating step (vi) until the electrodes have been immersed into each of the plurality of stable liquid suspensions, thereby depositing a multilayer coating onto the substrate.
5 more elements
A method of depositing a carbon nanotube film having a stable pulsed current higher than 10 mA over a 6 mm2 area for at least 1,000 pulses, the method comprising:
- (i) forming a suspension containing at least the carbon nanotubes and an adhesion promoting material in a liquid medium, the adhesion promoting material comprising one of the group selected from a carbon-dissolving material and a carbide-forming material, wherein the carbon-dissolving material is selected from the group consisting of nickel, iron, cobalt and manganese, and the carbide-forming material is selected from the group consisting-of silicon, molybdenum titanium, tantalum, tungsten, niobium, zirconium, vanadium, chromium, and hafnium;
- (ii) selectively adding a charger to the liquid medium;
- (iii) immersing electrodes in the suspension, wherein at least one of the electrodes comprises the substrate;
- and
- (iv) applying a direct or alternating current to the immersed electrodes thereby creating an electrical field between the electrodes;
- wherein the carbon nanotubes and the adhesion promoting material co-deposit on the substrate to form the composite film, the composite film having an intimate mix of the carbon nanotubes and the adhesion-promoting material, and further wherein the composite film has a stable pulsed current higher than 10 mA over a 6 mm2 area for at least 1,000 pulses.
3 more elements
A method of depositing a carbon nanotube film that displays 3% or less emission current decay after 10 hours, the method comprising:
- (i)forming a suspension containing at least the carbon nanotubes and an adhesion promoting material in a liquid medium, the adhesion promoting material comprising one of the group selected from a carbon-dissolving material and a carbide-forming material, wherein the carbon-dissolving material is selected from the group consisting of nickel, iron, cobalt and manganese, and the carbide-forming material is selected from the group consisting of silicon, molybdenum titanium, tantalum, tungsten, niobium, zirconium, vanadium, chromium, and hafnium;
- (ii) selectively adding a charger to the liquid medium;
- (iii) immersing electrodes in the suspension, wherein at least one of the electrodes comprises the substrate;
- and
- (iv) applying a direct or alternating current to the immersed electrodes thereby creating an electrical field between the electrodes;
- wherein the carbon nanotubes and the adhesion promoting material co-deposit on the substrate to form the composite film, the composite film having an intimate mix of the carbon nanotubes and the adhesion-promoting material, and further wherein the composite film displays 3% or less emission current decay after 10 hours.
3 more elements
An electrophoretic method of depositing a composite film comprising a carbon nanotube material onto a conducting substrate, the method comprising:
- (i) forming a liquid suspension comprising the carbon nanotubes, particles of adhesion-promoting material, and a charger, wherein the suspension has a nanotube concentration of 0.1-1.0 mg/mL, expressed as mg of carbon nanotubes per mL of liquid medium and wherein the particles of adhesion promoting material is selected from the group consisting of poly(vinyl butyral-co vinyl alcohol-co-vinyl acetate), poly(vinylidene fluoride), titanium, iron, lead, cobalt, nickel, tantalum, tungsten, niobium, zirconium, vanadium, chromium, hafnium, manganese, silicon, and molybdenum;
- (ii) immersing electrodes in the suspension, wherein at least one of the electrodes comprises the substrate;
- (iii) applying an electric field in the range of 0.1-1000 V/cm between the electrodes, wherein the nanotubes and the particles of adhesion-promoting material co-deposit on the substrate;
- and
- (iv) annealing the substrate, wherein the annealing comprises a two-step anneal comprising heating the coated substrate to 100-1200° C. for approximately 1 hour and then to approximately 800° C. for two hours.
2 more elements
A method of depositing a composite film onto one conducting surface of a substrate having at least two electrically insulated conducting surfaces, wherein the composite film comprises carbon nanotubes, the method comprising:
- (i) forming a liquid suspension comprising carbon nanotubes and particles of an adhesion promoting material in a liquid medium, wherein the adhesion promoting material is selected from the group consisting of a carbon-dissolving material and a carbide-forming material, wherein the carbon-dissolving material is selected from the group consisting of nickel, iron, cobalt and manganese, and the carbide-forming material is selected from the group consisting of silicon, molybdenum titanium, tantalum, tungsten, niobium, zirconium, vanadium, chromium, and hafnium;
- (ii) selectively adding a charger to the liquid medium;
- (iii) immersing electrodes in the suspension, wherein at least one of the electrodes comprises the substrate and another of the electrodes comprises a counter electrode, wherein the substrate comprising two electrically insulated conducting surfaces, surface A and surface B;
- (iv) applying an electrical field between surface A and the counter electrode, wherein the field strength is between 0.1-1000 V/cm, thereby causing the carbon nanotubes and the particles of the adhesion promoting material to migrate towards and co-deposit onto surface A;
- and
- (v) applying a small bias electrical field on surface B to prevent deposition of the carbon nanotubes and particles onto surface B.
3 more elements
Dependencies are inferred from the claim text.