Host Material Combination for OLED Charge Balance

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Solution Overview

Problem

Conventional organic electroluminescent devices using host materials with only hole-injecting substituents suffer from unbalanced charge injection and transport, leading to reduced efficiency and lifespan due to insufficient electron injection and transport characteristics.

Innovation Solution

A combination of specific host materials represented by formulas 1 and 2, which include compounds with varying substituents and linkages, are used to balance charge transport in organic electroluminescent devices, enhancing luminous efficiency and lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If host materials with strong hole injection characteristics are used alone, then hole transport is improved, but charge balance deteriorates

Engineering Contradiction:

Improveluminous efficiencyVSAvoidcharge balance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies parameter changes by systematically varying the chemical structure parameters of the host materials. Formula 1 and Formula 2 represent different parameter configurations of host materials with complementary charge transport properties. By adjusting substituents, molecular weights, and structural parameters in these formulas, the invention optimizes both hole and electron transport parameters to achieve balanced charge injection while maintaining high luminous efficiency.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If conventional host materials are used, then device structure is simple, but lifespan decreases due to unbalanced charge transport

Engineering Contradiction:

Improvematerial structureVSAvoidlifespan

Core Design Contradiction:

Device complexityVSDuration of action of stationary object

Solution Approach 1:

The patent uses composite materials by integrating multiple functional components into the host material system. Formula 1 and Formula 2 compounds are combined to create a composite host material that simultaneously provides hole injection, hole transport, electron injection, and electron transport functions, thereby extending device lifespan without significantly increasing structural complexity.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies universality by designing host materials that perform multiple functions. The combined Formula 1 and Formula 2 host material system universally provides both hole and electron transport capabilities, replacing the need for separate specialized materials and achieving multi-functionality within a unified material framework that maintains structural simplicity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20210184133A1Organic electroluminescent compound, a plurality of host materials, and organic electroluminescent device comprising the same

Publication Date: 2021.06.17 DUPONT SPECIALTY MATERIALS KOREA LTD

AI summary

The present disclosure relates to a plurality of host materials comprising a first host material comprising a compound represented by formula 1 and a second host material comprising a compound represented by formula 2 and an organic electroluminescent device comprising the same. By comprising an organic electroluminescent compound according to the present disclosure as an organic electroluminescent material or the specific combination of the compound as host materials, an organic electroluminescent device having high luminous efficiency and/or long lifespan can be provided compared with a conventional organic electroluminescent device.