Copper Oxide Electrochromic Coatings for Black-to-Transparent Switching

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing electrochromic materials struggle to achieve reversible color change between black and transparent states, particularly inorganic materials lacking stability and suitability for light-controlling glass applications.

Innovation Solution

Development of a black electrochromic material using copper oxide nanoparticles derived from basic copper carbonate, dispersed in a weakly acidic solvent, and combined with other oxide-based electrochromic materials to form a coating material that exhibits reversible color change between black and transparent states, along with a color-variable electrode and electrochromic device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If organic polymer materials are used to achieve black color, then color performance is improved, but light resistance deteriorates

Engineering Contradiction:
Improvecolor performanceVSAvoidlight resistance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent changes the material parameter from organic polymer to inorganic nanoparticle (copper oxide), fundamentally altering the material's optical and chemical properties to achieve both black color and light resistance simultaneously

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite system by dispersing copper oxide nanoparticles in a solvent matrix, combining the optical properties of inorganic nanoparticles with the processability of a composite coating material

Inventive Principle:
Principle #40Composite materials

2Reliability

If inorganic materials are used to improve light resistance, then reliability is improved, but color change reversibility deteriorates

Engineering Contradiction:
Improvelight resistanceVSAvoidcolor change reversibility
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent optimizes the particle size parameter of copper oxide nanoparticles to 1-100 nm, which enables reversible electrochromic color change while maintaining the light resistance advantages of inorganic materials

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces conventional bulk inorganic materials with nanoscale copper oxide particles, where quantum confinement effects enable reversible redox reactions that achieve both stability and color change reversibility

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If conventional inorganic materials are used, then manufacturing simplicity is maintained, but film smoothness and transparency deteriorate

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidfilm smoothness
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent controls the particle size of copper oxide nanoparticles within 1-100 nm and adjusts their concentration in the coating material to achieve smooth, transparent thin films while maintaining simple manufacturing processes

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent ensures uniform distribution of copper oxide nanoparticles throughout the coating material, creating locally homogeneous regions that form smooth, defect-free thin films on the electrode surface

Inventive Principle:
Principle #3Local quality

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 a stable and efficient electrochromic material that achieves a significant absorbance difference between colored and transparent states, suitable for light-controlling glass applications, enhancing light resistance and film formation.

Implementation Method 1

An electrochromic device (ECD) is a color-variable device that uses an electrochromic material (EC material), whose color changes by electrochemical redox reaction

Methodology Applied
Scientific EffectElectrochromism: Electrochromism

Implementation Method 2

the black electrochromic material comprises one or more nanoparticles selected from the group consisting of copper oxide nanoparticles that are heat-treated products of basic copper carbonate

Methodology Applied
Scientific EffectRedox reaction: Redox Reactions

Data Source

PatentEP4632035A1Black electrochromic material and method for manufacturing same, paint and method for manufacturing same, mixed paint and method for manufacturing same, color-variable electrode and method for manufacturing same, and electrochromic element
Publication Date: 2025.10.15 NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE & TECHNOLOGY
  • EP4632035A1 patent drawingFigure 1(a)~1(b)
  • EP4632035A1 patent drawingFigure 2
  • EP4632035A1 patent drawingFigure 3

AI summary

To provide an electrochromic material and a method for producing the same, which are used in a coating material that exhibits reversible color change between black and transparent, as well as a coating material and a mixed coating material containing the electrochromic material and methods for producing the same, a color-variable electrode, and an electrochromic device. [Solution] A black electrochromic material that reversibly changes color between black and transparent through an electrochemical redox reaction, comprising one or more nanoparticles selected from the group consisting of copper oxide nanoparticles that are heat-treated products of basic copper carbonate, titanium oxide nanoparticles, titanium nitride nanoparticles, nickel oxide nanoparticles, nickel hydroxide nanoparticles, zirconium oxide nanoparticles, and metallic iridium nanoparticles.