Crystalline Anodic Electrochromic Nanostructures for Flexible Smart Windows
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Solution Overview
Problem
The challenge is to develop low-cost, aesthetically appealing, and durable electrochromic window devices with crystalline anodic nanostructures that can be used in large area formats, particularly for smart windows, where conventional solid-state synthesis methods are limited by the need for high temperatures, which are not compatible with flexible substrates and require innovative methods for achieving crystallinity and high transmissivity modulation.
Innovation Solution
The development of crystalline anodic electrochromic nanostructures and thin films using low-temperature processes, where crystalline anodic electrochromic particles are synthesized, size-reduced, and coated onto substrates, enabling the creation of multi-layer stacks and devices that can modulate optical properties efficiently without exposing substrates to high temperatures, and incorporating these structures into electrochromic devices with ion-conducting layers and transparent conductive layers for reversible switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solid-state synthesis methods are used to prepare crystalline EC materials, then crystallinity and electrochemical performance are improved, but high processing temperatures are required which are incompatible with flexible substrates and increase manufacturing costs
Solution Approach 1:
The synthesis process is divided into two separate stages: (1) crystallization stage where EC particles are formed at high temperature in a crucible, and (2) deposition stage where the pre-crystallized particles are transferred and deposited onto the substrate at low temperature. This segmentation allows the substrate to avoid high temperature exposure while the EC material achieves full crystallinity in the first stage.
Solution Approach 2:
The EC particles are pre-crystallized before being deposited onto the substrate. By performing the crystallization action in advance (preliminarily) in a high-temperature resistant crucible, the subsequent deposition onto the temperature-sensitive substrate can occur at low temperature, preserving substrate integrity while ensuring material crystallinity.
2Reliability
If high-temperature processing is used to achieve crystallinity, then electrochemical performance is improved, but substrate damage and manufacturing costs increase
Solution Approach 1:
The process separates the high-temperature crystallization step from the low-temperature deposition step. The EC material is crystallized in a crucible that can withstand high temperatures, then the crystallized particles are transferred to the substrate at low temperature, preventing substrate damage while maintaining electrochemical performance.
Solution Approach 2:
A crucible serves as an intermediary container that temporarily holds the EC material during high-temperature crystallization. This intermediary protects the substrate from direct exposure to high temperatures while still allowing the EC material to achieve full crystallinity in the crucible before being transferred to the substrate.
3Temperature
If low-temperature processes are used to protect substrates, then substrate compatibility is improved, but achieving crystallinity and high transmissivity modulation becomes difficult
Solution Approach 1:
Crystallization is performed as a preliminary action before deposition onto the substrate. The EC particles are fully crystallized in a high-temperature resistant crucible first, then these pre-crystallized particles are deposited onto the substrate at low temperature. This preliminary crystallization ensures that the material achieves full crystallinity without requiring the substrate to withstand high temperatures.
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 approach allows for the production of electrochromic devices with improved optical and electrical properties, including high optical transmission, coloration efficiency, and durability, while enabling the use of flexible substrates and reducing manufacturing costs by avoiding high-temperature processing.
Implementation Method 1
reversibly change from a more bleached (e.g., a relatively greater optical transmissivity) to a more darkened state (e.g., a relatively lesser optical transmissivity)
Implementation Method 2
charge balance is maintained by mobile cations entering and leaving the electrodes
Data Source
AI summary
A method of manufacturing a thin film is provided. The method includes providing a plurality of crystalline anodic electrochromic particles, size-reducing the crystalline anodic electrochromic particles by grinding to produce crystalline hexagonal tungsten trioxide nanostructures, and coating the crystalline anodic electrochromic nanostructures onto a substrate to produce a thin film. An electrochromic multi-layer stack is also provided.