Dual Host Material System for OLED Efficiency and Lifetime

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Solution Overview

Problem

Existing organic electroluminescent devices face challenges in achieving high luminous efficiency and long lifetime, which are essential for long-term use and high-resolution displays.

Innovation Solution

The use of a specific combination of host materials, comprising a first host material represented by a particular compound formula and a second host material represented by another compound formula, is proposed to enhance the performance of organic electroluminescent devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional host materials are used in organic electroluminescent devices, then the device can operate, but the luminous efficiency is insufficient and lifetime is short

Engineering Contradiction:

Improveluminous efficiencyVSAvoiddevice lifetime

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent employs a composite host material system comprising two distinct compounds: a first host material with formula (1) featuring carbazole derivatives with specific substituent patterns, and a second host material with formula (2) containing fluorescent dopant compounds. This composite approach allows the first host to provide structural stability and charge transport while the second host contributes to enhanced luminous efficiency through its fluorescent properties, thereby simultaneously improving both reliability and device lifetime beyond what single materials could achieve alone

Inventive Principle:

Principle #40Composite materials

2Reliability

If phosphorescent materials are used to achieve high luminous efficiency, then the device requires specific host materials that limit design flexibility

Engineering Contradiction:

Improveluminous efficiencyVSAvoidhost material design flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by providing specific substituent patterns at defined positions in the molecular structure. For the first host material, the formula specifies particular arrangements of aromatic rings and substituent groups at defined locations, while the second host material's formula specifies fluorescent dopant positions. This localized structural optimization ensures high luminous efficiency at the emission center while maintaining overall molecular stability and compatibility with standard OLED architectures

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by systematically varying molecular parameters such as substituent types, ring fusion patterns, and dopant concentrations within the defined formulas. The first host material allows variation in carbazole substitution patterns while maintaining the core structure, and the second host material permits adjustment of fluorescent dopant characteristics. These parameter adjustments enable optimization of luminous efficiency while preserving host-guest interactions necessary for device operation

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12289996B2Plurality of host materials and organic electroluminescent device comprising the same

Publication Date: 2025.04.29 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 a specific combination of compounds of the present disclosure as host materials, it is possible to provide an organic electroluminescent device having higher luminous efficiency and/or longer lifetime properties as compared with a conventional organic electroluminescent device.