NiWNbO Counter Electrode Stack for Faster Stable Electrochromics
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Solution Overview
Problem
Existing electrochromic devices suffer from issues such as material stability over time, slow switching speed, and undesirable optical properties, particularly in tungsten oxide and nickel oxide materials, limiting their commercial potential.
Innovation Solution
The development of a novel electrochromic stack using a cathodically coloring layer of tungsten oxide (WOx) and an anodically coloring layer of nickel tungsten niobium oxide (NiWNbO) with specific atomic ratios, deposited directly in contact without an ion conductor layer, and an integrated deposition system for precise layer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrochromic materials (tungsten oxide and nickel oxide) are used, then the device can achieve basic electrochromic function, but material stability over time deteriorates
Solution Approach 1:
The patent applies composite materials by combining nickel oxide, tungsten oxide, and niobium oxide in specific ratios to create a counter electrode material that achieves both stability and long service life. The composite structure allows the materials to complement each other's properties, with nickel oxide providing anodic coloring, tungsten oxide providing cathodic coloring, and niobium oxide enhancing stability, thereby resolving the contradiction between reliability and duration of action.
2Speed
If conventional electrochromic materials are used, then the device can operate, but switching speed deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the atomic ratios of nickel, tungsten, and niobium in the counter electrode material, as well as controlling deposition parameters during sputtering. By adjusting these parameters, the material achieves faster ion transport kinetics (improving switching speed) while maintaining structural stability (preserving reliability).
3Illumination intensity
If conventional electrochromic materials are used, then the device can function, but optical properties deteriorate (tinted states too blue, transparent states too yellow)
Solution Approach 1:
The patent applies local quality by creating a multi-component counter electrode material where each component contributes specific optical properties. The nickel oxide, tungsten oxide, and niobium oxide are distributed in specific proportions to achieve neutral coloring in the tinted state and minimal yellowing in the transparent state, thereby improving optical clarity while maintaining ease of manufacture through a single-material solution.
4Ease of operation
If a separate ion conductor layer is used between cathodically and anodically coloring layers, then ion transport can occur, but device complexity increases
Solution Approach 1:
The patent applies merging by integrating the ion conductor function directly into the counter electrode material itself, eliminating the need for a separate ion conductor layer. The nickel tungsten niobium oxide composite material possesses both counter electrode functionality (anodic coloring) and ion conductor properties, thereby reducing device complexity while maintaining ion transport efficiency.
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 solution provides improved material stability, faster switching speeds, and more aesthetically pleasing tinted and clear states, enhancing the commercial viability of electrochromic devices.
Implementation Method 1
The anodically coloring layer may be formed by sputtering one or more sputter targets to form the NiWNbO
Implementation Method 2
Electrochromism is a phenomenon in which a material exhibits a reversible electrochemically-mediated change in an optical property when placed in a different electronic state, typically by being subjected to a voltage change
Data Source
AI summary
The embodiments herein relate to electrochromic stacks, electrochromic devices, and methods and apparatus for making such stacks and devices. In various embodiments, an anodically coloring layer in an electrochromic stack or device is fabricated to include nickel-tungsten-niobium-oxide (NiWNbO). This material is particularly beneficial in that it is very transparent in its clear state.