Solid-State Electrochromic Device with Mixed Metal Oxide Active Layer
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Solution Overview
Problem
Existing redox electrochromic devices (ECDs) face limitations due to the use of liquid or gel solutions, which restrict stability and operating temperature range, and lack a solid-state configuration with a single solid active layer.
Innovation Solution
A solid-state electrochromic device with a single active layer comprising a mixture of transition metal oxides, such as tungsten oxide and praseodymium oxide, is developed, where the active layer is deposited on a conducting surface and topped with a transparent electrode, allowing for rapid optical transparency changes in response to external potentials without relying on ion intercalation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid or gel solutions are used in redox electrochromic devices, then the device can achieve electrochromic effect, but the stability and operating temperature range are limited
Solution Approach 1:
The patent changes the physical state parameter from liquid/gel to solid, transforming the electrochromic material into a solid-state system. This parameter change eliminates the limitations of liquid and gel solutions regarding stability and temperature range, while maintaining the electrochromic functionality through solid-phase redox reactions.
Solution Approach 2:
The patent employs composite solid-state materials comprising multiple metal oxides (such as tungsten oxide, molybdenum oxide, titanium oxide) combined with conductive polymers or salts. These composite solid materials achieve both stability and broad temperature operating range while enabling the electrochromic effect through coordinated redox reactions of the constituent materials.
2Reliability
If liquid or gel solutions are used in redox electrochromic devices, then the electrochromic effect can be achieved, but the device structure becomes complex and less stable
Solution Approach 1:
The patent extracts and removes the liquid or gel electrolyte component from the device structure, replacing it with a solid-state electrochromic layer. This extraction simplifies the overall device architecture by eliminating the need for separate electrolyte layers, ion storage layers, and complex sealing structures required to contain liquids and gels.
Solution Approach 2:
The patent merges the electrochromic active material and the electrolyte function into a single integrated solid layer. The solid-state redox-active materials simultaneously perform electron transfer and ion mediation functions that were previously separated into different components, thereby simplifying the device structure while enhancing stability.
3Speed
If traditional redox electrochromic devices use multiple layers and ion intercalation, then the electrochromic effect is achieved, but the response time is slower
Solution Approach 1:
The patent segments the electrochromic function into discrete solid redox couples within the active layer, allowing independent and simultaneous electron transfer reactions. This segmentation enables parallel redox processes that occur rapidly without requiring the sequential ion intercalation steps needed in multi-layer ionic devices, thereby achieving faster response times.
Solution Approach 2:
The patent substitutes the mechanical ion intercalation process with electronic electron transfer mechanisms in solid-state redox reactions. Instead of relying on slow diffusion and mechanical insertion of ions through multiple layers, the device uses rapid electronic redox reactions at the solid-electrode interface, achieving significantly faster optical response times while reducing the number of required layers.
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 device achieves rapid optical transmittance changes within milliseconds and operates effectively across a broader temperature range, enhancing stability and performance compared to traditional redox ECDs.
Implementation Method 1
it is known to make a reduction-oxidation ECD ('redox ECD') that operates via molecular oxidation-reduction reactions rather than by moving intercalating ions among various layers within the device
Implementation Method 2
electrochromic devices characterized by an optical transparency that varies responsive to an external potential applied between two electrodes
Data Source
AI summary
A solid-state electronic electrochromic device (ECD) operates electronically rather than relying on the ionic motion that is common in electrochromic devices. The electronic ECD has at least one active layer sandwiched between two electrodes. The active layer is made of mixed metal oxides and may be made of a mixture of tungsten and praseodymium oxides. The electronic ECD may have only a single active layer, or may have multiple layers that have the same composition and that are separated by thin transparent metal films. Some versions of the electronic ECD incorporate a distribution of small metal particles within the active layer.