Electrochromic Metal Oxide Films via Inert Spray Pyrolysis

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Solution Overview

Problem

Existing methods for depositing transition metal oxide films for electrochromic applications face challenges such as high cost, low cycling durability, inadequate switching range and speed, and issues with film uniformity and porosity, particularly with spray pyrolysis methods where carrier gases like air or nitrogen can cause precipitates and low deposition rates.

Innovation Solution

A precursor solution containing additives like viscosity enhancers, bases, acids, and structural promoter ions is used, deposited under an inert atmosphere with inert gases, to form nanocrystalline metal oxide films that are fully reversible and resistant to ambient moisture, improving film properties and deposition efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If spray pyrolysis method is used to deposit transition metal oxide films, then deposition cost is reduced and large-area coatings are achieved, but film uniformity deteriorates and precipitates form due to use of air or nitrogen as carrier gases

Engineering Contradiction:

Improvedeposition costVSAvoidfilm uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies inert atmosphere principle by replacing air or nitrogen with argon as the carrier gas in spray pyrolysis process. Argon creates an inert environment that prevents precipitate formation and improves film uniformity while maintaining the cost-effectiveness and large-area coating capabilities of spray pyrolysis. This directly resolves the contradiction between ease of manufacture and manufacturing precision.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Ease of manufacture

If conventional electrochromic materials are used, then initial cost is reduced, but cycling durability deteriorates and switching range is inadequate

Engineering Contradiction:

Improveinitial costVSAvoidcycling durability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies parameter changes principle by modifying the chemical composition parameters of the electrochromic material through specific precursor formulations and deposition conditions. This results in nanocrystalline metal oxide films with improved cycling durability and switching range while maintaining cost-effectiveness. The parameter optimization resolves the contradiction between initial cost and reliability.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If vacuum deposition techniques are used, then film quality is improved, but device complexity and cost increase

Engineering Contradiction:

Improvefilm qualityVSAvoidvacuum system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies mechanics substitution principle by replacing complex vacuum deposition systems with a simpler spray pyrolysis process. The spray pyrolysis method achieves comparable or superior film quality without requiring sophisticated vacuum equipment, thereby reducing device complexity and cost while maintaining manufacturing precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Ease of manufacture

If spray pyrolysis is used with air or nitrogen carrier gases, then deposition rate is reduced and precipitates form, but manufacturing cost remains low

Engineering Contradiction:

Improvemanufacturing costVSAvoiddeposition rate

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent applies inert atmosphere principle by using argon as the carrier gas, which eliminates precipitate formation and maintains high deposition rates. This resolves the contradiction between manufacturing cost and productivity, as argon-based spray pyrolysis achieves both low cost and high deposition rate without the drawbacks of air or nitrogen.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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 results in metal oxide films with enhanced switching range, speed, and cycling durability, reduced light scattering, and lower manufacturing costs, while maintaining electrochromic properties and stability over extended cycles.

Implementation Method 1

the deposition of an electrochemically active transition metal oxide film onto the surface of a glass sheet by a wet chemical process such as sol-gel

Methodology Applied

Scientific EffectSol-gel: Sol

Implementation Method 2

The term 'electrochromic' refers to the ability of certain materials to change color when an electrical potential is applied

Methodology Applied

Scientific EffectElectrochromism: Electrochromism

Implementation Method 3

EC devices work by intercalation and deintercalation of mobile ions

Methodology Applied

Scientific EffectIntercalation: Absorption (physical)

Data Source

PatentUS9904137B1Electrochromic materials and fabrication methods

Publication Date: 2018.02.27 CLEARIST

AI summary

A precursor solution adapted to provide a metal oxide film, includes: (a) at least one additive selected from a viscosity enhancer, a base, an acid and a wetting agent; (b) structural promoter ions selected from Mn, Ni, Co, Ir, Ru, Cr, Mo, W, Ta, Nb, V, Mo, Zr, V and Ti ions; and (c) at least one solvent. A method for preparing a metal oxide film includes: (a) providing a substrate; and (b) depositing on the substrate the precursor solution of the invention. Metal oxides films, electrochromic devices containing the films and methods for making them are also disclosed.