Tristate Electrochromic Device Selective Radiation Absorption
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Solution Overview
Problem
Conventional electrochromic devices are limited in their ability to selectively absorb visible or near-infrared radiation based on applied potential, restricting their application in varying environmental conditions such as temperature and lighting needs.
Innovation Solution
A tristate electrochromic device is developed using a medium comprising electroactive anodic and cathodic materials that can operate in three states: maximum light transmission, variable attenuation of either visible or near-infrared radiation, and variable attenuation of the other spectral region, allowing for selective absorption of radiation based on applied potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional electrochromic devices are used, then they can absorb radiation, but they cannot selectively absorb visible or near-infrared radiation based on applied potential
Solution Approach 1:
The electrochromic device is segmented into multiple functional layers with distinct materials: a first electrochromic material (e.g., tungsten oxide) for visible light absorption and a second electrochromic material (e.g., nickel oxide) for near-infrared absorption. Each layer can be independently controlled through applied potential, enabling selective absorption in different spectral regions. This segmentation allows the device to achieve tristate operation (visible-only, NIR-only, or both) without requiring entirely separate device structures.
Solution Approach 2:
The device employs composite electrochromic materials with complementary absorption characteristics. The first electrochromic material exhibits strong visible light absorption when electrochemically switched, while the second material provides near-infrared absorption. By combining these materials in a multi-layer configuration within a single device, the system achieves broadband spectral control and tristate functionality, resolving the contradiction between selectivity and complexity.
2Temperature
If the device absorbs both visible and near-infrared radiation, then thermal comfort is improved, but visual comfort deteriorates due to reduced light transmission
Solution Approach 1:
The device dynamically adjusts its optical properties by independently controlling the electrochemical state of each electrochromic material layer through separate potential applications. Users can switch between states: (1) both materials reduced for maximum visible transmission and NIR blocking, (2) first material reduced and second material oxidized for visible transmission with selective NIR absorption, or (3) both materials oxidized for simultaneous visible and NIR absorption. This dynamic control allows real-time optimization of both thermal and visual comfort based on environmental conditions.
Solution Approach 2:
The device changes its optical transmission parameters by controlling the oxidation state of each electrochromic material layer. The first material (e.g., tungsten oxide) transitions between reduced (transparent to visible) and oxidized (absorbing visible) states, while the second material (e.g., nickel oxide) transitions between reduced (transparent to NIR) and oxidized (absorbing NIR) states. By independently adjusting these parameter changes through applied potential, the system achieves selective spectral control to balance thermal and visual comfort requirements.
3Object-affected harmful factors
If the device blocks visible radiation, then glare is reduced, but illumination decreases
Solution Approach 1:
The device segments the spectral control function into two independent material systems: the first electrochromic material primarily controls visible light transmission, and the second electrochromic material primarily controls near-infrared transmission. This segmentation enables selective blocking of visible radiation (to reduce glare) while maintaining near-infrared transmission (for thermal comfort), or vice versa, by independently controlling the electrochemical state of each material layer through applied potential.
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 tristate electrochromic device effectively manages temperature and illumination by selectively absorbing radiation, optimizing environmental conditions such as temperature and reducing glare and unwanted illumination effects across different times of day and seasons.
Implementation Method 1
an electrochromic medium, and, in turn, an electrochromic device, to operate between at least three regions or states... wherein variable attenuation of either visible radiation or near-infrared radiation occurs to a significant extent depending on the device configuration
Implementation Method 2
a potential difference less than that sufficient to cause electrochemical oxidation or reduction of the anodic and cathodic materials is applied
Implementation Method 3
a potential difference less than that sufficient to cause electrochemical oxidation or reduction of the anodic and cathodic materials is applied
Data Source
AI summary
An electrochromic medium for use in a tristate electrochromic device, comprising: (a) at least one solvent; (b) at least one anodic material; (c) at least one cathodic material, wherein both of the anodic and cathodic materials are electroactive and at least one of the anodic and cathodic materials is electrochromic; (d) wherein, in a first state, the electrochromic medium exhibits a maximum light transmission; (e) wherein, in a second state, variable attenuation occurs to a significant extent in one of visible radiation or near-infrared radiation without significant attenuation in the other; and (f) wherein, in a third state, variable attenuation occurs to a significant extent in the other spectral region.