Electrochromic Module Using Tetraarylbenzidine Polymer
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Solution Overview
Problem
Existing electrochromic materials face limitations in achieving multiple color states, long-term stability, and efficient switching kinetics due to issues like irreversible redox forms, color contrast degradation, and poor solubility, which restrict their application in multi-color displays and filters.
Innovation Solution
A tetraarylbenzidine-diol condensation polymer is used in combination with a polymer gel electrolyte and an ion storage layer, allowing for reversible redox reactions and achieving multiple color states with high electrochromic contrast and efficiency, while being simple and cost-effective to produce.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional electrochromic materials (viologen, tungsten oxide, polythiophene, PEDOT-PSS) are used, then two-color switching is achieved, but multi-color capability is limited
Solution Approach 1:
The patent applies parameter changes by systematically modifying the chemical structure of tetraphenylbenzidine polymers through varying substituents (alkoxy groups, halogen atoms, cyano groups, hydrocarbon radicals) and divalent radicals to achieve different color states. This enables the single polymer material to exhibit multi-chromism with at least three distinct color states, resolving the contradiction between versatility and productivity.
2Reliability
If metallocenes and stabilization materials are added to improve service life, then anodic partial reaction stability is improved, but color contrast decreases and lifespan is reduced due to yellow-brown layer formation
Solution Approach 1:
The patent extracts and eliminates the harmful metallocene stabilization materials from the electrochromic system. Instead of using metallocenes that cause yellow-brown layer formation and color contrast degradation, the invention relies on the intrinsic stability of the tetraphenylbenzidine polymer structure combined with a polymer gel electrolyte, thereby removing the source of harmful effects while maintaining reliability.
Solution Approach 2:
The patent replaces expensive metallocene stabilization materials with a cost-effective polymer gel electrolyte system that provides equivalent or superior stability without the harmful side effects. The polymer gel electrolyte (PVDF-HFP with lithium salt in ionic liquid) offers long-term stability at lower cost and without generating yellow-brown degradation products.
3Object-generated harmful factors
If conventional polymers (polypyrrole, polyaniline) are used, then electrochromic activity is achieved, but electrical stability deteriorates due to air sensitivity
Solution Approach 1:
The patent employs composite materials by combining the tetraphenylbenzidine polymer with a polymer gel electrolyte system consisting of PVDF-HFP matrix, lithium salt, and ionic liquid. This composite structure provides both electrochromic activity and enhanced electrochemical stability, protecting the polymer from air sensitivity while maintaining electrical properties over thousands of switching cycles.
4Reliability
If rigid encapsulation is applied to protect EC modules from external influences, then reliability is improved, but flexibility is impaired
Solution Approach 1:
The patent uses a polymer gel electrolyte system that inherently provides protection while maintaining flexibility. The gel structure (PVDF-HFP matrix) acts as both the electrolyte medium and a protective layer, eliminating the need for rigid encapsulation. This flexible gel structure protects the electrochromic polymer from external influences while preserving device flexibility and bendability.
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 electrochromic module exhibits stable performance over 10,000 switching cycles with high contrast and efficient switching kinetics, maintaining transparency in the neutral state and achieving orange and blue colors with low voltage, suitable for various applications including displays and glazing.
Implementation Method 1
one on which A coating made of an electrochromic polymer arranged on the first substrate or the first conductive coating... The electrochromic module according to the invention is characterized by the fact that it can be switched reversibly between more than two color states in a voltage-controlled manner
Implementation Method 2
Redox-active materials such as tungsten oxide, viologen or various polymers such as polythiophene, polyethylenedioxythiophene (PEDOT), polyaniline, etc. are reversibly electrochemically oxidized and reduced, changing their color
Implementation Method 3
an electrolyte arranged electrically in series between the electrochromic coating and the ion storage layer... a polymer gel electrolyte and an ion storage layer
Data Source
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AI summary
A description is given of an electrochromic module comprising a first substrate and a second substrate, wherein the first and/or the second substrate are/is electrically conductive or are/is respectively equipped with an electrically conductive coating, a coating composed of an electrochromic polymer arranged on the substrate or the conductive coating, an ion storage layer arranged on the substrate or the conductive coating, and an electrolyte disposed electrically in series connection between the electrochromic coating and the ion storage layer. The electrochromic polymer is a substantially linear condensation polymer composed of a tetraarylbenzidine and a (hetero)aromatic diol, which can be switched reversibly between more than two redox states in a voltage-controlled manner, wherein the condensation polymer is colourless in one redox state and coloured in at least two redox states. The electrolyte is a polymer gel electrolyte. With just one electrochromic material, it is possible to represent more than two colour states and at the same time to achieve a large number of switching cycles without an appreciable decrease in the electrochromic properties, a high electrochromic contrast and a high electrochromic efficiency of the modules with effective switching kinetics.