Metal Iridium Complex Ligand Design for OLED Efficiency

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Solution Overview

Problem

Current organic electroluminescent devices face challenges in luminous efficiency, driving voltage, service life, color saturation, and thermal stability, particularly with phosphorescent materials, which fail to meet the requirements of the OLED market for high performance and color gamut.

Innovation Solution

The development of metal iridium complexes with specific ligand structures, such as Ir(La)(Lb)(Lc), which exhibit improved optical and electrical stability, high luminous efficiency, and long device life, suitable for use as red luminescent phosphorescent materials in organic light-emitting devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If phosphorescent materials are used to improve luminous efficiency, then luminous efficiency is improved, but device lifetime and thermal stability deteriorate

Engineering Contradiction:

Improveluminous efficiencyVSAvoiddevice lifetime

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent modifies the molecular structure parameters of phosphorescent iridium complexes by introducing specific ligands (formula 1 and formula 2) with particular substituent groups, changing the electronic and steric properties to achieve both high efficiency and improved stability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates composite ligand systems combining formula 1 ligands with formula 2 ligands in the iridium complex, where the synergistic interaction between different ligand types achieves both high luminous efficiency and enhanced device lifetime

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If phosphorescent materials are used to improve luminous efficiency, then luminous efficiency is improved, but color saturation and thermal stability deteriorate

Engineering Contradiction:

Improveluminous efficiencyVSAvoidcolor saturation

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent adjusts the molecular parameters of the iridium complex by selecting specific ligands with particular electronic properties and steric configurations, which modifies the emission characteristics to achieve both high efficiency and saturated color

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces local structural features at specific positions in the ligand molecules (such as the substituent groups in formula 1 and formula 2) that locally enhance color saturation while maintaining overall thermal stability

Inventive Principle:

Principle #3Local quality

3Reliability

If conventional iridium compounds are used, then device performance is improved, but luminous efficiency and device lifetime deteriorate

Engineering Contradiction:

Improvedevice performanceVSAvoidluminous efficiency

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent develops a composite ligand system where formula 1 ligands combine with formula 2 ligands to create an iridium complex that achieves synergistic effects, improving both device performance and luminous efficiency simultaneously

Inventive Principle:

Principle #40Composite materials

4Stability of the object's composition

If red luminescent materials are developed for deeper red color, then color gamut is improved, but device efficiency and lifetime deteriorate

Engineering Contradiction:

Improvecolor gamutVSAvoiddevice efficiency

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent modifies the HOMO-LUMO energy gap parameters of the iridium complex by adjusting ligand structures, which shifts the emission wavelength to deeper red while maintaining high device efficiency and lifetime through optimized molecular orbitals

Inventive Principle:

Principle #35Parameter changes

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 metal iridium complexes demonstrate enhanced luminous efficiency, extended device life, and improved color saturation, meeting the demands of the OLED industry for display and lighting applications, including automobile taillights, with potential for deeper red color development and reduced energy consumption.

Implementation Method 1

due to spin-orbit coupling caused by heavy-atom effect, phosphorescent materials can utilize the energy of 75% triplet excitons in addition to the 25% singlet state

Methodology Applied

Scientific EffectSpin-orbit coupling:

Implementation Method 2

due to spin-orbit coupling caused by heavy-atom effect, phosphorescent materials can utilize the energy of 75% triplet excitons

Methodology Applied

Scientific EffectHeavy-atom effect:

Implementation Method 3

holes and electrons are recombined in a luminous layer and released in the form of light or heat, thus producing the luminescence of the OLEDs

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS20240336836A1Metal iridium complex and electroluminescent device

Publication Date: 2024.10.10 GUANGDONG AGLAIA OPTOELECTRONICS MATERIALS

AI summary

The present invention relates to a metal iridium complex and an electroluminescent device. The metal iridium compound has a general formula of Ir(La)(Lb)(Lc), wherein La is a structure shown in formula (1), and Lb is a structure shown in formula (2). The compound provided in the present invention can be used in organic light-emitting devices, particularly as a red luminescent phosphorescent material, and has the potential to be applied to the AMOLED industry, particularly for display, lighting, and automobile taillights.