Undercoating Layers for Photoactive Topcoat Functionality
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Solution Overview
Problem
Conventional multi-layer coated articles, such as those used in solar cells and photocatalytic applications, face issues with high surface resistivity, sodium ion diffusion, visible light reflectance, and aesthetic concerns like iridescence, which hinder their performance and appearance.
Innovation Solution
A coated article with a substrate and a first undercoating layer comprising a mixture of oxides like silica, titania, and alumina, followed by a photoactive top coating, is developed using chemical vapor deposition, which reduces surface resistivity, suppresses color and reflectance, and enhances photocatalytic activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transparent conductive film is used in solar cells, then electron flow is enabled, but surface resistivity remains high which limits electron movement speed
Solution Approach 1:
The patent divides the coating system into multiple layers: a base transparent conductive film and an additional functional coating layer containing conductive materials. This segmentation allows each layer to contribute differently - the base layer provides transparency while the functional layer reduces surface resistivity, resolving the contradiction between transparency and conductivity.
Solution Approach 2:
The patent uses composite materials by combining transparent conductive oxide materials with additional conductive materials in a multi-layer coating structure. This composite approach enables the coating to simultaneously achieve low surface resistivity and high transparency, as each material component contributes its specific properties to the overall system.
2Reliability
If conventional photocatalytic coatings are applied, then photocatalytic activity is achieved, but visible light reflectance increases and aesthetic appearance deteriorates
Solution Approach 1:
The patent applies color suppression technology by incorporating specific materials and coating structures that reduce visible light reflectance. The functional coating is designed to suppress unwanted reflections and color effects while maintaining photocatalytic functionality, thereby improving aesthetic appearance without sacrificing photocatalytic activity.
Solution Approach 2:
The patent modifies optical parameters of the coating by controlling thickness, composition, and refractive index of different layers. By adjusting these parameters, the coating achieves reduced visible light reflectance and minimized iridescence while preserving the photocatalytic properties of the titania layer.
3Reliability
If conventional photocatalytic coatings are used, then photocatalytic function is provided, but sodium ion diffusion from substrate degrades coating performance
Solution Approach 1:
The patent introduces an intermediate functional coating layer between the glass substrate and the photocatalytic titania layer. This intermediate layer acts as a barrier that prevents sodium ion diffusion from the substrate into the photocatalytic coating, thereby protecting the coating performance while allowing the photocatalytic function to operate effectively.
Solution Approach 2:
The patent applies the functional coating layer in advance, before the photocatalytic titania layer, to establish a protective barrier against sodium ion diffusion. This preliminary action prevents the harmful effect from occurring in the first place, ensuring long-term stability of the photocatalytic coating.
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 solution significantly reduces surface resistivity, minimizes reflectance, and increases photocatalytic activity, improving the functionality and aesthetic appeal of coated articles in photovoltaic and photocatalytic applications.
Implementation Method 1
A coated article with a substrate and a first undercoating layer comprising a mixture of oxides like silica, titania, and alumina, followed by a photoactive top coating, is developed using chemical vapor deposition
Implementation Method 2
the undercoating layer could decrease the surface resistivity of the top coat (e.g., a transparent conductive layer) to increase electron flow. In photocatalytic applications, the undercoating layer could increase the photocatalytic activity of the photocatalytic coating
Implementation Method 3
Upon exposure to certain electromagnetic radiation, such as ultraviolet radiation, the photocatalytic coating interacts with organic contaminants on the coating surface to degrade or decompose the organic contaminants
Implementation Method 4
conventional photocatalytic coatings can be subject to degradation through what is conventionally termed 'sodium ion poisoning' caused by sodium ions defusing from the underlying glass substrate into the photocatalytic coating
Data Source
AI summary
A coated article includes a substrate and a first coating formed over at least a portion of the substrate. The first coating includes a mixture of oxides including oxides of at least two of P, Si, Ti, Al and Zr. A photoactive functional coating is formed over at least a portion of the first coating. In one embodiment, the functional coating includes titania.