Electrochromic Buffer Layer for Fast High-Contrast Switching
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Solution Overview
Problem
Conventional electrochromic devices face challenges in achieving a significant differential between high and low light transmission states and rapid switching between these states while maintaining optimal conductivity and longevity.
Innovation Solution
The introduction of a buffer layer in the electrochromic device configuration, which includes a first transparent electrode, an electrochromic layer, an electrolyte layer, a second electrochromic layer, and a second transparent electrode, where the buffer layer promotes electron transfer and inhibits deleterious chemical interactions, enabling rapid and efficient switching between high and low transparency states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrochromic devices use two active layers separated by an electrolyte layer, then the device can achieve light transmission modulation, but the device suffers from poor reliability and poor performance with slow switching speeds and insufficient transmittance differential
Solution Approach 1:
The patent divides the electrochromic device into four distinct layers: first electrochromic layer, electrolyte layer, second electrochromic layer, and buffer layer. This segmentation allows each layer to perform its specific function optimally, with the buffer layer specifically designed to maintain conductivity and enable rapid ion transport between layers, thus improving both reliability and switching speed simultaneously
Solution Approach 2:
The buffer layer acts as an intermediary between the second electrochromic layer and the electrode, facilitating rapid ion transport while maintaining electrical conductivity. This intermediary layer resolves the contradiction by providing a dedicated pathway for ion movement that doesn't compromise the overall device reliability
2Illumination intensity
If conventional electrochromic devices use two active layers, then the device can modulate light transmission, but the differential between high and low light transmission states is insufficient
Solution Approach 1:
The patent employs composite material structure with four functional layers, each composed of specific materials optimized for their function. The combination of electrochromic materials in both active layers, coupled with the electrolyte and buffer layers, creates a composite system that achieves superior light transmission differential (at least 70% difference) while maintaining manageable device complexity through clear functional division
3Duration of action of stationary object
If conventional electrochromic devices operate over extended periods, then the device can provide continuous light modulation, but the device conductivity deteriorates and lifespan is reduced
Solution Approach 1:
The buffer layer performs self-service by automatically maintaining electrical conductivity and stabilizing the electrochemical environment during prolonged operation. It self-regulates ion concentration and pH levels, ensuring consistent performance over thousands of cycles without external intervention, thus extending lifespan while maintaining reliability
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 configuration allows for a rapid change between high and low transparency states, achieving at least a 70% difference in transmittance, with switching times as short as 5 seconds, and extends the device's lifespan by maintaining conductivity and stability.
Implementation Method 1
Conventional electrochromic devices change light transmission and/or light reflection upon the application of an external DC voltage
Implementation Method 2
an electrolyte layer formed on the first electrochromic layer and positioned between the first electrochromic layer and a second electrochromic layer, the electrolyte layer is configured to selectively transfer ions from the first electrochromic layer to the second electrochromic layer upon selective application of electrical potential
Implementation Method 3
a buffer layer formed on the second electrochromic layer and positioned between the second electrochromic layer and the second transparent electrode that is configured to maintain conductivity and stability of the electrochromic device while in use; the buffer layer promotes electron transfer between the second transparent electrode and second electrochromic layer
Data Source
AI summary
Electrochromic devices having buffer layer(s) that promote electron transfer between the second transparent electrode and second electrochromic layer while concurrently reducing or inhibiting deleterious chemical interaction between the second electrochromic layer and the second electrode and/or maintaining the conductive state of the second electrode and while the device changes the from a low transparency state of approximately 10-20% transmittance in the visible region to a high transparency state of approximately 75% to 95% transmittance in the visible region with at least a 70% difference in transmittance between the low and high transmittance states. In certain aspects, the electrochromic devices change from a low transparency state having a gray color to a high transparency state that is substantially colorless within 20 seconds of applying the selective electrical potential to the electrochromic device.