Condensed Cyclic Compound for OLED Charge Transport and Heat Resistance

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Solution Overview

Problem

Organic light-emitting devices face challenges in durability and efficiency due to high driving voltage and short lifespan, primarily attributed to the limitations in charge transport and heat resistance within the organic layer and between the organic layer and electrodes.

Innovation Solution

Incorporation of a condensed cyclic compound, represented by Formula 1, which enhances charge transport capability, increases inter-molecular stacking, and improves heat resistance, thereby reducing driving voltage and extending the device's lifespan by acting as a material in the hole transport region, electron transport region, or emission layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional organic materials are used in the organic layer, then the device structure is simple, but the driving voltage is high and the lifespan is short

Engineering Contradiction:
Improvedevice structureVSAvoidlifespan
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces a condensed cyclic compound with specific molecular structure parameters (Formula 1) that has high glass transition temperature and rigid structure. This changes the physical and chemical parameters of the organic layer material, improving charge transport capability and heat resistance, thereby extending device lifespan without complicating the overall device structure

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite approach by incorporating the condensed cyclic compound as a host material in the emission layer or as a transport material in charge transport regions. This composite material strategy combines the benefits of the condensed cyclic structure (high Tg, rigid framework) with appropriate dopants or auxiliary materials to achieve both high reliability and maintained structural simplicity

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If conventional organic materials are used in the organic layer, then the manufacturing process is simple, but the heat resistance is poor

Engineering Contradiction:
Improvemanufacturing processVSAvoidheat resistance
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The condensed cyclic compound in Formula 1 possesses inherently high glass transition temperature due to its rigid molecular framework and condensed cyclic structure. This parameter change in the material's thermal properties directly improves heat resistance during device operation and manufacturing processes, while the compound's compatibility with standard organic electronics fabrication techniques maintains ease of manufacture

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If conventional organic materials are used in the organic layer, then the device operation is simple, but the charge transport capability is limited

Engineering Contradiction:
Improvedevice operationVSAvoidcharge transport capability
Core Design Contradiction:
Ease of operationVSPower

Solution Approach 1:

The condensed cyclic compound's rigid planar structure and extended π-conjugation system change the electrical parameters of the organic layer by providing efficient charge transport pathways. This improves charge mobility and transport capability, reducing operating voltage and improving device efficiency while maintaining simple operation through standard device architecture

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The condensed cyclic compound acts as an intermediary material that facilitates charge transport between electrodes and emission layers. Its high charge mobility serves as a bridge, improving overall charge transport capability across the device without requiring complex multi-layer structures or additional processing steps

Inventive Principle:
Principle #24Intermediary (Mediator)

4Device complexity

If conventional organic materials are used in the organic layer, then the material structure is simple, but the inter-molecular stacking is insufficient

Engineering Contradiction:
Improvematerial structureVSAvoidinter-molecular stacking
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The condensed cyclic compound's molecular geometry and rigid structure change the packing parameters and intermolecular interaction strength. This promotes efficient π-π stacking and molecular organization in the solid state, improving charge transport and device reliability while maintaining relatively simple material synthesis and device fabrication processes

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 use of the condensed cyclic compound results in an organic light-emitting device with improved durability, reduced driving voltage, and increased efficiency, along with enhanced heat resistance, leading to a longer lifespan.

Implementation Method 1

enhances charge transport capability, increases inter-molecular stacking

Methodology Applied
Scientific EffectCharge transport: Conduction (electrical)

Implementation Method 2

improves heat resistance, leading to a longer lifespan

Methodology Applied
Scientific EffectHeat resistance: Thermal Insulation

Data Source

PatentEP3296288B1Condensed cyclic compound and organic light-emitting device including the same
Publication Date: 2020.08.12 SAMSUNG DISPLAY CO LTD
  • EP3296288B1 patent drawingFigure 1
  • EP3296288B1 patent drawingFigure 2
  • EP3296288B1 patent drawingFigure 3

AI summary

A condensed cyclic compound and an organic light-emitting device including the same, the condensed cyclic compound being represented by Formula 1: