Tungsten-Doped Tin Oxide Coating via Spray Pyrolysis
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Solution Overview
Problem
Current transparent conductive coatings, such as indium-doped tin(IV) oxide and fluorine-doped tin(IV) oxide, face challenges including high costs, complexity in processing, and toxicity issues, while existing tungsten-doped tin oxide coatings have complex production methods and limited stability.
Innovation Solution
A coated substrate with a crystalline tungsten-doped tin oxide coating produced through spray pyrolysis using a solution containing soluble tin and tungsten compounds in an organic solvent, with controlled oxygen exposure and ultrasound application, achieving a layer thickness of 170 to 5000 nm and high mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sputtering is used to produce transparent conductive coatings, then electrical conductivity and optical transparency are improved, but process complexity increases and toxic byproducts are generated
Solution Approach 1:
The patent replaces the mechanical sputtering process with a chemical spray pyrolysis method. Instead of using a vacuum sputtering apparatus to deposit ITO or FTO coatings, the invention uses a spray nozzle to apply a liquid precursor solution containing tungsten and tin compounds, which then undergoes pyrolytic decomposition on a heated substrate to form the TCO coating. This substitution eliminates the complex vacuum system and moving parts while achieving comparable electrical conductivity and optical transparency.
Solution Approach 2:
The patent uses inexpensive tungsten-doped tin oxide precursors in liquid form instead of expensive indium-containing materials like ITO. The liquid precursor solution can be easily prepared and applied, and the resulting TTO coating provides similar functional performance at lower material cost and without the environmental concerns associated with fluorine-based materials.
2Reliability
If indium-doped tin(IV) oxide is used for transparent conductive coatings, then electrical conductivity is improved, but manufacturing cost increases
Solution Approach 1:
The patent substitutes expensive indium-containing materials with cheaper tungsten-doped tin oxide precursors. The liquid precursor solution contains tungsten and tin compounds that are significantly less expensive than indium, yet the resulting TCO coating achieves comparable electrical conductivity and optical transparency, thereby reducing material costs while maintaining performance.
Solution Approach 2:
The patent changes the chemical composition parameters by using tungsten doping instead of indium doping in the tin oxide matrix. This compositional parameter change results in a material (TTO) that has similar electrical and optical properties to ITO but at lower cost, addressing the manufacturing cost issue while preserving the essential functional parameters.
3Reliability
If fluorine-doped tin(IV) oxide is used for transparent conductive coatings, then electrical conductivity is improved, but toxicity of byproducts increases
Solution Approach 1:
The patent replaces fluorine-doped tin oxide with tungsten-doped tin oxide, using a liquid precursor solution containing tungsten and tin compounds. This substitution eliminates fluorine from the material system, thereby preventing the formation of toxic fluorine-containing byproducts during deposition and processing, while maintaining the electrical conductivity performance through tungsten doping.
Solution Approach 2:
The patent converts the potential harm of using toxic fluorine-based materials into a benefit by selecting tungsten-doped tin oxide precursors that are environmentally friendly and non-toxic. The liquid precursor formulation allows for controlled deposition without generating harmful emissions, transforming the material selection into an environmentally beneficial process while achieving the desired electrical conductivity.
4Reliability
If pulse plasma deposition is used to produce tungsten-doped tin oxide films, then electrical conductivity is improved, but process complexity and production time increase
Solution Approach 1:
The patent replaces the complex pulse plasma deposition process with a simpler spray pyrolysis method. Instead of using plasma generation equipment and complex timing sequences for pulsed deposition, the invention uses a spray nozzle to apply liquid precursor that undergoes thermal decomposition on a heated substrate. This eliminates the need for plasma generation and complex pulsing control, significantly reducing production time while achieving comparable electrical conductivity.
Solution Approach 2:
The patent utilizes phase transitions of the liquid precursor solution during spray pyrolysis. The liquid precursor is sprayed onto a heated substrate where it undergoes evaporation and pyrolytic decomposition, transitioning from liquid to solid TCO coating. This phase transition mechanism enables rapid coating formation without the need for complex plasma processing or long sintering times, thereby improving productivity while maintaining electrical conductivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method provides a cost-effective, stable, and highly conductive crystalline tungsten-doped tin oxide coating with improved mechanical stability and reduced toxicity, suitable for various substrates, including ceramics and polymeric materials, with adjustable layer thickness and conductivity.
Implementation Method 1
a) spray pyrolyzing a solution containing at least one soluble tin compound and at least one soluble tungsten compound in a solvent in the presence of oxygen or oxygen-releasing compound(s) to produce a crystalline tungsten-doped tin oxide-containing layer
Implementation Method 2
spray pyrolyzing a solution containing at least one soluble tin compound and at least one soluble tungsten compound in a solvent in the presence of oxygen or oxygen-releasing compound(s)
Implementation Method 3
with controlled oxygen exposure and ultrasound application, achieving a layer thickness of 170 to 5000 nm and high mechanical stability
Data Source
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AI summary
The present invention relates to an electrically conductive coating comprising crystalline tungsten-doped tin oxide, wherein the electrically conductive coating has a layer thickness in the range of 170 to 5000 nm and comprises columnar tungsten-doped tin oxide.