Bipolar Spiro Organic Compound for OLED Emissive Layer

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Solution Overview

Problem

Conventional OLEDs face limitations in luminous efficiency and lifetime due to the short luminous lifetime of metal complex phosphorescent materials, particularly for blue emission, and the low efficiency of conventional fluorescent materials which only utilize singlet excitons.

Innovation Solution

An organic compound with a high excited triplet energy level and bipolar properties is introduced, featuring a spiro moiety with n-type properties and a hetero aromatic moiety with p-type properties, which is used in the emissive layer to enhance luminous efficiency and stability, allowing for efficient exciton energy transfer and balanced charge injection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If phosphorescent metal complex materials are used to achieve high luminous efficiency, then luminous efficiency is improved, but luminous lifetime becomes too short for commercial application

Engineering Contradiction:

Improveluminous efficiencyVSAvoidluminous lifetime

Core Design Contradiction:

Loss of energyVSDuration of action of stationary object

Solution Approach 1:

The patent changes the chemical composition parameters by using organic compounds instead of metal complexes, and adjusts molecular structure parameters (such as introducing spiro moieties and hetero aromatic groups) to achieve both high luminous efficiency and extended lifetime without relying on phosphorescent metal complexes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces expensive and short-lived phosphorescent metal complexes with organic compounds that can achieve comparable or superior performance with longer operational stability, making the system more suitable for commercial devices

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Device complexity

If conventional fluorescent materials are used, then material simplicity is maintained, but luminous efficiency is low due to only singlet excitons involvement

Engineering Contradiction:

Improvematerial complexityVSAvoidluminous efficiency

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent creates composite organic compounds combining spiro moieties with hetero aromatic groups to achieve bipolar properties, enabling both holes and electrons to participate in luminescence and significantly improving luminous efficiency while maintaining organic material simplicity

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The organic compound is designed to perform multiple functions: it acts as both host and emitter, provides bipolar charge transport, and achieves high triplet energy level, eliminating the need for separate phosphorescent materials while improving overall device efficiency

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If blue emission materials are used, then color diversity is achieved, but luminous properties and luminous lifetime are deteriorated

Engineering Contradiction:

Improvecolor emission capabilityVSAvoidluminous properties and lifetime

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces specific local structural features (spiro moieties and hetero aromatic groups) into the organic compound to enhance thermal stability and triplet energy level locally, which improves overall luminous properties and lifetime while maintaining blue emission capability

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 organic compound improves luminous efficiency, extends the lifetime of OLEDs, and reduces driving voltage, while maintaining excellent thermal stability and color purity by enabling efficient exciton energy transfer and balanced charge injection.

Implementation Method 1

efficient exciton energy transfer

Methodology Applied

Scientific EffectExciton energy transfer: Fluorescence

Implementation Method 2

high luminous efficiency

Methodology Applied

Scientific EffectLuminescence: Luminescence

Implementation Method 3

balanced charge injection

Methodology Applied

Scientific EffectCharge injection: Electron Beam

Implementation Method 4

high affinity to electrons

Methodology Applied

Scientific EffectElectron transport: Conduction (electrical)

Data Source

PatentUS12171144B2Organic compound, organic light emitting diode and organic light emitting device including the organic compound

Publication Date: 2024.12.17 LG DISPLAY CO LTD

AI summary

The present disclosure relates to an organic compound having the following structure, and an organic light emitting diode (OLED) and an organic light emitting device including the organic compound. The organic compound can be a bipolar compound having a p-type moiety and an n-type moiety and has high energy level and proper energy bandgap for an emissive layer of the OLED. As the organic compound is applied into the emissive layer, the OLED can maximize its luminous properties as holes and electrons are recombined uniformly over the whole area in an emitting material layer (EML).