Doped Silver IR Reflecting Layer for Low-E Coating Stability
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Solution Overview
Problem
Conventional low-E coatings with silver IR reflecting layers face issues with chemical durability and stability, leading to degradation of optical, electrical, and thermal properties, especially in harsh environmental conditions, limiting their application in window units and energy-saving capabilities.
Innovation Solution
Doping the silver IR reflecting layer with silicon (Si) and aluminum (Al), or combinations like Si and zinc (Zn), or Si, Zn, and copper (Cu), enhances corrosion resistance, chemical durability, and stability, while maintaining good optical properties such as high light-to-solar gain ratios, even after heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a silver based IR reflecting layer is used in low-E coating, then good optical properties and low emissivity are achieved, but chemical durability and environmental stability deteriorate
Solution Approach 1:
The patent applies composite materials by doping silver with silicon and aluminum to create AgSiAl doped silver. This composite structure combines the excellent optical properties of pure silver with the enhanced chemical durability of silicon and aluminum dopants, resolving the contradiction between maintaining good optical properties and improving chemical durability.
Solution Approach 2:
The patent changes the compositional parameters of the silver layer by introducing specific dopants (silicon and aluminum) in controlled amounts. This parameter change transforms the pure silver material into a doped composite that maintains optical performance while significantly improving chemical durability and environmental stability.
2Stability of the object's composition
If conventional silver IR reflecting layers are used, then low emissivity properties are maintained, but stability under harsh environmental conditions deteriorates
Solution Approach 1:
By creating AgSiAl doped silver composite material, the patent enhances the stability of the silver layer composition. The silicon and aluminum dopants form a more stable structure that resists environmental degradation, directly addressing the stability and environmental durability issues of conventional silver layers.
3Reliability
If silver layers are doped to improve chemical durability, then corrosion resistance improves, but optical properties may deteriorate
Solution Approach 1:
The patent carefully controls the doping parameters by limiting silicon content to 0.1-20 atomic percent and aluminum content to 0.1-10 atomic percent. This precise parameter control ensures that the chemical durability is improved while the optical properties remain intact, as the dopant concentrations are kept low enough not to significantly alter the optical behavior of the silver layer.
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 doped silver IR reflecting layers improve chemical durability and stability, maintaining high light-to-solar gain ratios and reducing haze, thus enhancing the performance and longevity of low-E coatings in window applications.
Implementation Method 1
an infrared (IR) reflecting layer of silver that is doped... The IR reflecting layer(s) is part of a low emissivity (low-E) coating... block significant amounts of IR radiation
Data Source
AI summary
Example embodiments of this invention relate to a coated article having a low-E coating including at least one infrared (IR) reflecting layer of silver that is doped with a material such as SiAl, SiZn, or SiZnCu. The IR reflecting layer(s) is part of a low-E coating, and may be sandwiched between at least transparent dielectric layers. A silver based IR reflecting layer doped in such a manner for example provides for improved corrosion resistance and chemical durability of the layer and the overall coating, and improved stability such as reduced haze upon optional heat treatment (HT), while maintaining good optical properties, compared to an Ag IR reflecting layer that is not doped.