Dual Host Materials for Low-Temperature OLED Deposition

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Solution Overview

Problem

Existing organic electroluminescent devices face challenges with materials that require high deposition temperatures, leading to denaturation and degradation of luminescent properties, and there is a need for materials that can maintain excellent hole and electron properties while allowing for lower deposition temperatures.

Innovation Solution

The combination of specific compounds represented by formulas 1 and 2 as host materials in the light-emitting layer, which separate HOMO and LUMO parts to improve hole and electron properties, allowing for favorable thermal denaturation at lower deposition temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high molecular weight host materials are used to improve hole and electron properties, then luminescent properties are improved, but deposition temperature increases causing material denaturation and deterioration of luminescent properties

Engineering Contradiction:

Improveluminescent propertiesVSAvoiddeposition temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The host material is divided into two separate compounds (Formula 1 and Formula 2) with distinct functions: Formula 1 provides hole transport capability while Formula 2 provides electron transport capability. This segmentation allows each compound to have optimized molecular weight and structure for its specific function, enabling deposition at lower temperatures while maintaining excellent luminescent properties.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses a composite system consisting of two different host compounds (Formula 1 and Formula 2) combined in the light-emitting layer. This composite approach allows the material system to achieve superior hole and electron properties through complementary functions, while individual components can be deposited at lower temperatures avoiding denaturation.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If high deposition temperature is applied to deposit host materials, then complete deposition is achieved, but material denaturation occurs deteriorating inherent properties

Engineering Contradiction:

Improvedeposition completenessVSAvoidinherent properties

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the physical and chemical parameters of the host materials by selecting compounds with specific molecular structures (Formula 1 and Formula 2) that have appropriate volatility and thermal stability characteristics. This allows deposition to be completed at lower temperatures, preventing denaturation while ensuring complete layer formation.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If single host material is used to simplify device structure, then manufacturing is easier, but both hole and electron properties cannot be optimized simultaneously

Engineering Contradiction:

Improvematerial structureVSAvoidhole and electron properties

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The host material function is segmented into two separate compounds: Formula 1 specialized for hole transport and Formula 2 specialized for electron transport. This functional segmentation allows each material to be optimized for its specific charge carrier type, achieving superior overall device performance despite increased material complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the light-emitting layer exhibit different local qualities through the use of Formula 1 and Formula 2. Formula 1 predominates in regions requiring hole transport while Formula 2 predominates in regions requiring electron transport, optimizing charge carrier properties locally throughout the device.

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

This combination results in organic electroluminescent devices with lower driving voltage, higher luminous efficiency, and longer lifetime, while maintaining thermal stability and electronic properties.

Implementation Method 1

An OLED changes electric energy into light by applying electricity to an organic light-emitting material

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

a host material should have high purity and a suitable molecular weight in order to be deposited under vacuum

Methodology Applied

Scientific EffectVacuum deposition: Physical Vapour Deposition

Data Source

PatentEP3685453B1A plurality of host materials and organic electroluminescent device comprising the same

Publication Date: 2025.07.23 DUPONT SPECIALTY MATERIALS KOREA LTD

AI summary

The present disclosure relates to a plurality of host materials and organic electroluminescent devices comprising the same. The present disclosure may provide a plurality of host materials having a composition favorable to thermal denaturation due to a low deposition temperature, while improving hole properties and electronic properties of HOMO and LUMO, by comprising separate compounds represented by formulas 1 and 2 into a light-emitting layer. By comprising the plurality of host materials of the present disclosure, it is possible to provide an organic electroluminescent device having a lower driving voltage, higher luminous efficiency and/or longer lifetime.