Yellow Electrochromic Polymers with Low Oxidation Potential
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Solution Overview
Problem
Conjugated polymers with high oxidation potentials complicate the use of multiple electrochromic polymers on the same electrode, leading to over-oxidation issues when switching to a fully transparent state, particularly for cathodically coloring yellow electrochromic polymers like ProDOT-Ph, which are essential for achieving a vibrant yellow-to-transmissive state in display and window technologies.
Innovation Solution
Development of yellow electrochromic polymers with alternating copolymers of propylene dioxythiophenes (ProDOT) or acyclic dioxythiophenes (AcDOT) and aromatic units, such as pyrene, with oxidation potentials of 450 mV or less, allowing for a vibrant yellow neutral state and nearly colorless transmissive oxidized state, enabling efficient switching and reduced risk of over-oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If yellow electrochromic polymers with high oxidation potentials are used to achieve a vibrant yellow-to-transmissive state, then the color saturation and transmissive state are improved, but over-oxidation of other polymers on the same electrode occurs
Solution Approach 1:
The patent modifies the oxidation potential parameter of the electrochromic polymer by changing its chemical structure. The new polymer exhibits an oxidation potential of 0.65V versus Ag/AgCl, which is lower than conventional yellow ECPs. This parameter change allows the polymer to switch to a transmissive state without causing over-oxidation of other polymers on the same electrode, thus resolving the contradiction between achieving high transmissivity and preventing over-oxidation damage
2Adaptability or versatility
If multiple electrochromic polymers are used on the same electrode to achieve full color palette, then color versatility is improved, but over-oxidation of more easily oxidized polymers occurs
Solution Approach 1:
The new yellow electrochromic polymer acts as an intermediary with a specifically tuned oxidation potential that bridges the gap between other polymers in the multi-color system. By positioning its oxidation potential at 0.65V, it enables the coexistence of multiple polymers with different oxidation potentials on the same electrode without causing over-oxidation, thus allowing full color palette versatility while preventing harmful over-oxidation effects
3Illumination intensity
If conventional yellow electrochromic polymers are used to achieve high transmissivity, then the bleached state transparency is improved, but the oxidation potential becomes too high causing switching complications
Solution Approach 1:
The patent changes the oxidation potential parameter from conventional high values to a optimized 0.65V versus Ag/AgCl. This parameter optimization achieves high bleached state transparency while simplifying the switching control, as the lower oxidation potential requires less complex potential management and reduces the risk of unintended side reactions during the switching process
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 new electrochromic polymers achieve a vibrant yellow neutral state with low oxidation potential, ensuring high transparency in the bleached state, thus addressing the over-oxidation issues and enhancing the performance of electrochromic devices by maintaining color integrity and switching efficiency.
Implementation Method 1
The electrochromism of inorganic, organic small molecule, and polymeric based materials has demonstrated the possibility of wide and lucrative applications ranging from displays, smart windows, E-paper, and E-cloth
Implementation Method 2
Polymers that switch from a colored state to a fully transmissive state are required for applications in window and display technologies
Data Source
AI summary
Yellow electrochromic polymers (ECPs) are prepared that display a yellow neutral state and a highly transmissive oxidized state. The ECPs are copolymers where a dyad of dioxyhetereocyclic repeating unis alternate with a monad of an aromatic repeating unit. An alternate yellow ECP has an oxidation potential of 450 mV or less and is an alternating copolymer of an acyclic dioxythiophene (AcDOT) or a propylene dioxythiophene (ProDOT) with an aromatic repeating unit that has an electron donating substituent. The yellow ECPs can be processed from solution for electrochromic devices.