P-Type Metal Oxide Barrier Layer for Longer-Life Organic Electronics

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Solution Overview

Problem

Organic electronic devices suffer from poor gas barrier properties and short lifespan due to the use of organic materials, leading to degradation from environmental factors such as heat, moisture, and gases, which affects devices like electrophotographic photoconductors, dye-sensitized solar cells, and organic EL devices.

Innovation Solution

A laminated structure is formed using a silicone-containing layer and a metal oxide film with p-type semiconductivity, specifically delafossite-type metal oxides, to enhance adhesion and density, improving gas barrier properties and device durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If organic materials are used in electronic devices, then ease of manufacture and cost are improved, but gas barrier property and lifespan deteriorate

Engineering Contradiction:
Improveease of manufactureVSAvoidgas barrier property
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention uses composite materials by combining organic materials with inorganic metal oxide particles (having p-type semiconductivity) to create a hybrid structure. The metal oxide particles are dispersed in the organic binder resin, forming a protective layer that provides both the manufacturability of organic materials and the gas barrier properties of inorganic materials, thereby resolving the contradiction between ease of manufacture and gas barrier property.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention applies local quality by creating a specific protective layer with metal oxide particles at the surface or interface where gas barrier protection is most needed. This layer is formed by coating or laminating metal oxide-containing composition onto the organic electronic device, providing localized enhancement of gas barrier properties without requiring the entire device to be made of inorganic materials.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If organic materials are used in electronic devices, then ease of manufacture is improved, but lifespan deteriorates due to degradation from heat, moisture, and gases

Engineering Contradiction:
Improveease of manufactureVSAvoidlifespan
Core Design Contradiction:
Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The composite structure of organic binder resin with dispersed metal oxide particles creates a protective barrier that extends device lifespan. The inorganic metal oxide particles provide resistance to heat, moisture, and gas degradation while the organic binder maintains ease of manufacture, thus resolving the contradiction between ease of manufacture and lifespan.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention applies beforehand cushioning by pre-forming a protective layer containing metal oxide particles on the organic electronic device before exposure to harsh environmental conditions. This protective layer acts as a barrier that cushions the device against degradation from heat, moisture, and gases, extending lifespan while maintaining the ease of manufacture of organic materials.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If a protective layer with metal oxide particles is formed, then gas barrier property and wear resistance are improved, but device complexity increases

Engineering Contradiction:
Improvegas barrier propertyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention applies segmentation by dividing the protective function into a separate, distinct layer containing metal oxide particles that is coated or laminated onto the organic electronic device. This segmented approach allows the protective layer to be manufactured and applied independently, simplifying the overall manufacturing process while providing enhanced gas barrier properties, thus resolving the contradiction between gas barrier property and device complexity.

Inventive Principle:
Principle #1Segmentation

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 laminated structure enhances the lifespan and durability of electronic devices by providing improved resistance to environmental factors, maintaining high-quality image and photoelectric conversion performance.

Implementation Method 1

organic electronic devices have a drawback that their lifespan is shorter than that of inorganic electronic devices. One of the causes is that a gas barrier property derived from the organic materials contained in the organic electronic devices is poor

Methodology Applied
Scientific EffectGas barrier property: Permeation

Implementation Method 2

A laminated structure is formed using a silicone-containing layer and a metal oxide film with p-type semiconductivity, specifically delafossite-type metal oxides, to enhance adhesion and density

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP4154329B1Electronic device comprising metal oxide particles having p-type semiconductivity, method for manufacturing electronic device, and image forming apparatus
Publication Date: 2025.12.31 RICOH CO LTD
  • EP4154329B1 patent drawingFigure 1
  • EP4154329B1 patent drawingFigure 2
  • EP4154329B1 patent drawingFigure 3

AI summary

Metal oxide particles having p-type semiconductivity are provided. The metal oxide particles have a volume-based particle size distribution having a first local maximum value and a second local maximum value. The first local maximum value is in a range of 0.1 µm or more and less than 5 µm and the second local maximum value is in a range of 5 µm or more and less than 50 µm. A ratio of the second local maximum value to the first local maximum value is 0.5 or more and less than 2.0, and 99% by volume or more of the metal oxide particles have a particle diameter in a range of from 0.1 to 50 µm.