Organometallic Compound for OLED Emission Layer Stability

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Solution Overview

Problem

Current organic light-emitting devices face challenges in achieving high luminescent efficiency and chemical stability due to interactions between emitting compounds and host materials, leading to reduced performance and lifespan.

Innovation Solution

An organometallic compound represented by Formula 1 is introduced, featuring a specific substructure that reduces electron density and structural steric hindrance, allowing for improved chemical stability and emission characteristics, including deep blue light emission and both phosphorescence and fluorescence efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional emitting compounds are used in organic light-emitting devices, then device structure is simple, but luminescent efficiency decreases and chemical stability deteriorates due to interactions with host materials

Engineering Contradiction:

Improvechemical stabilityVSAvoidcompound structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The emitting compound is divided into distinct functional modules: a metal center (M11) coordinated with organic ligands containing specific substructures. This segmentation allows independent optimization of each module - the metal center provides luminescent properties while the ligand substructures provide steric protection and electronic tuning, resolving the contradiction between stability and complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention creates a composite organometallic compound where a metal center is coordinated with organic ligands featuring specific substructures. This composite structure combines the luminescent properties of metal complexes with the steric and electronic properties of organic molecules, achieving both high luminescent efficiency and chemical stability simultaneously

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If emitting compounds with high electron density are used, then luminescent efficiency improves, but excimer and exciplex formation increases leading to reduced device lifespan

Engineering Contradiction:

Improveluminescent efficiencyVSAvoiddevice lifespan

Core Design Contradiction:

Use of energy by moving objectVSDuration of action of stationary object

Solution Approach 1:

The ligand substructures are designed in advance to prevent harmful interactions before they occur. The electron-withdrawing groups and steric barriers are pre-positioned to counteract the tendency toward excimer and exciplex formation, allowing high electron density to be maintained without the harmful consequences

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The invention converts the potentially harmful high electron density into a beneficial feature by using electron-withdrawing substructures that channel the electron density in controlled ways. These same substructures that reduce electron density also prevent excimer formation, turning what would be a harmful interaction into a protective mechanism

Inventive Principle:

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

3Duration of action of stationary object

If organometallic compounds with complex substructures are introduced to reduce excimer formation, then device lifespan extends, but manufacturing complexity increases

Engineering Contradiction:

Improvedevice lifespanVSAvoidcompound synthesis ease

Core Design Contradiction:

Duration of action of stationary objectVSEase of manufacture

Solution Approach 1:

Rather than making the entire molecule complex, the invention introduces specific localized substructures (electron-withdrawing groups and steric barriers) at key positions in the ligand framework. This localized approach provides the necessary protection against excimer formation while keeping the rest of the molecule relatively simple and easier to synthesize

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

The organometallic compound enhances the optical characteristics of organic light-emitting devices by improving luminescent efficiency and extending device lifespan through reduced excimer and exciplex formation, while maintaining chemical and physical stability.

Implementation Method 1

both phosphorescence and fluorescence efficiency

Methodology Applied

Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 2

both phosphorescence and fluorescence efficiency

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Implementation Method 3

Carriers, such as holes and electrons, recombine in the emission layer to produce excitons. These excitons transit from an excited state to a ground state, thereby generating light.

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS11925104B2Organometallic compound and organic light-emitting device including the same

Publication Date: 2024.03.05 SAMSUNG DISPLAY CO LTD

AI summary

Provided are an organometallic compound represented by Formula 1 and an organic light-emitting device including the same. The organic light-emitting device includes: a first electrode; a second electrode; an organic layer disposed between the first electrode and the second electrode, the organic layer including an emission layer and the organometallic compound represented by Formula 1.