Low Defectivity Electrochromic Devices via Integrated Deposition
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Solution Overview
Problem
Electrochromic devices face issues with realizing their full commercial potential due to various problems such as defects, limited durability, and inefficiencies in switching between optical states, which affect their reliability and scalability for applications like architectural glass.
Innovation Solution
The development of electrochromic materials and devices that incorporate a novel composition for the counter electrode, including anodically coloring metals and additives, along with a specific structure for the electrochromic stack, which includes a substrate, conductive layers, an electrochromic layer, an ion conducting layer, and a counter electrode layer, optimized for reduced defects and enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrochromic materials and structures are used, then the basic electrochromic function is achieved, but the devices suffer from high defectivity and limited durability
Solution Approach 1:
The patent applies composite materials by combining anodically coloring electrochromic materials with specifically selected additives in the counter electrode layer. This composite structure reduces defectivity and improves device durability by creating a more stable and defect-free interface between layers, directly addressing the reliability-manufacturing precision contradiction.
Solution Approach 2:
The patent changes material composition parameters by selecting specific additives from groups including Ag, Au, Cu, Pd, Pt, and others in controlled concentrations (e.g., 0.1-10 wt%). These parameter changes in the counter electrode composition reduce manufacturing defects and improve device reliability without compromising the electrochromic function.
2Productivity
If electrochromic devices are fabricated with conventional materials, then the device can be manufactured, but switching efficiency between optical states is limited
Solution Approach 1:
The patent optimizes switching efficiency by changing the compositional parameters of the counter electrode, specifically incorporating additives that facilitate faster and more complete ion transfer. This enables the device to cycle between optical states more efficiently and reliably, addressing both productivity and reliability concerns.
Solution Approach 2:
The additives in the counter electrode act as intermediaries that facilitate the electrochemical reactions and ion transfer between the electrochromic layer and the external circuit. This intermediary function improves switching efficiency and reliability by mediating the electrochemical processes more effectively.
3Duration of action of moving object
If the counter electrode uses standard materials, then the device structure is simple, but the device cannot maintain performance over 50,000 cycles
Solution Approach 1:
The patent extends cycle life to over 50,000 cycles by using composite counter electrode materials that combine anodically coloring materials with stability-enhancing additives. While this increases compositional complexity, it dramatically improves the duration of action and long-term performance maintenance.
Solution Approach 2:
The patent applies beforehand cushioning by incorporating stabilizing additives into the counter electrode composition prior to device operation. These additives preemptively prevent degradation mechanisms, cushioning against performance loss over time and enabling the device to maintain functionality through 50,000+ cycles.
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
This approach results in electrochromic devices that are more reliable, durable, and efficient in switching between states, suitable for large-scale applications like architectural glass, with reduced defectivity and improved longevity, enabling them to cycle between optical states over 50,000 times while maintaining transmissivity and color quality.
Implementation Method 1
Electrochromism is a phenomenon in which a material exhibits a reversible electrochemically-mediated change in an optical property when placed in a different electronic state, typically by being subjected to a voltage change.
Implementation Method 2
The counter electrode material may include an anodically coloring electrochromic material
Data Source
AI summary
Prior electrochromic devices frequently suffer from high levels of defectivity. The defects may be manifest as pin holes or spots where the electrochromic transition is impaired. This is unacceptable for many applications such as electrochromic architectural glass. Improved electrochromic devices with low defectivity can be fabricated by depositing certain layered components of the electrochromic device in a single integrated deposition system. While these layers are being deposited and/or treated on a substrate, for example a glass window, the substrate never leaves a controlled ambient environment, for example a low pressure controlled atmosphere having very low levels of particles. These layers may be deposited using physical vapor deposition. In certain embodiments, the device includes a counter electrode having an anodically coloring electrochromic material in combination with an additive.