Halogen-Substituted Organic Compound in Electron Injection Transport Layer

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Solution Overview

Problem

The challenge in developing light-emitting elements is the need for high-purity materials and precise atmospheric control to minimize halogen impurities, which increases manufacturing costs and affects the reliability and longevity of the elements, particularly in the electron-transport and electron-injection layers.

Innovation Solution

A light-emitting element structure with an electron injection transport layer containing a halogen-substituted organic compound that releases halogen upon electron injection, maintaining halogen concentration below 30 ppm, and having an energy threshold of less than 1.00 eV for halogen release in a radical anion state, ensuring minimal luminance decay over extended driving times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-purity materials and precise atmospheric control are used to minimize halogen impurities, then the reliability and lifespan of the light-emitting element are improved, but the manufacturing cost increases

Engineering Contradiction:

Improvelifespan of light-emitting elementVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses a halogen-substituted organic compound in the electron injection transport layer that is designed to release halogen intentionally during operation. This sacrificial approach allows the use of lower-purity materials overall, as the halogen release is controlled and localized to specific layers, reducing the need for expensive high-purity materials throughout the entire device structure.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the chemical composition parameters by introducing a halogen-substituted organic compound with specific properties (energy threshold less than 1.00 eV for halogen release) into the electron injection transport layer. This parameter change allows controlled halogen release that protects the light-emitting layer, enabling the use of more cost-effective materials while maintaining reliability.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If halogen concentration is kept below 30 ppm in the electron injection transport layer, then luminance decay is prevented and element performance is maintained, but material selection and purification requirements become more stringent

Engineering Contradiction:

Improveluminance stabilityVSAvoidhalogen concentration control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent converts the harmful effect of halogen impurities into a beneficial function by using a halogen-substituted organic compound that intentionally releases halogen. This controlled halogen release protects the light-emitting layer from degradation, transforming what is typically a harmful impurity into a protective mechanism that extends element lifespan and maintains luminance stability.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The halogen-substituted organic compound acts as an intermediary between the electron injection transport layer and the light-emitting layer. It releases halogen that migrates to protect the light-emitting layer, mediating the interaction between these layers and enabling the use of lower-purity materials in the light-emitting layer while maintaining overall device reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 results in a reliable and cost-effective light-emitting element with prolonged lifespan and stable luminance, as the controlled halogen release prevents luminance decay and maintains the element's performance even after prolonged use.

Implementation Method 1

Methodology Applied

Scientific EffectElectron injection:

Implementation Method 2

having an energy threshold of less than 1.00 eV for halogen release in a radical anion state

Methodology Applied

Scientific EffectHalogen release from radical anion state:

Implementation Method 3

voltage application between electrodes, between which a light-emitting layer is interposed, causes recombination of electrons and holes injected from the electrodes, which brings a light-emitting substance (an organic compound) into an excited state, and the return from the excited state to the ground state is accompanied by light emission

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS10074822B2Light-emitting element, light-emitting device, electronic device, and lighting device

Publication Date: 2018.09.11 SEMICON ENERGY LAB CO LTD

AI summary

To provide a novel light-emitting element or a highly reliable light-emitting element. To provide a light-emitting device, a display device, an electronic device, and a lighting device each of which can be manufactured at a low cost. To provide a light-emitting element including an anode, a cathode, and an EL layer between the anode and the cathode. The EL layer includes a light-emitting layer and an electron injection transport layer between the light-emitting layer and the cathode, and the amount of a halogen detected from a material forming the electron injection transport layer is less than or equal to 30 ppm.