Novel Hole Transport Compound for Organic Electronic Device Stability

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Solution Overview

Problem

Current organic light emitting devices face challenges in achieving high efficiency, long lifespan, and thermal stability due to limitations in material properties such as energy levels, electrochemical stability, and interfacial characteristics, particularly with materials like NPB and PEDOT:PSS.

Innovation Solution

A novel compound represented by Formula 1 is introduced, which forms aromatic rings and includes specific substituent groups, allowing for control of energy band gaps and improving interfacial characteristics, suitable for use as a hole injection or transport material, enhancing the performance of organic electronic devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If NPB is used as hole transport layer material, then the device can be manufactured, but the glass transition temperature is 100°C or lower making it difficult to apply to high current devices

Engineering Contradiction:
Improveglass transition temperatureVSAvoidthermal stability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent modifies the molecular structure of hole transport materials by introducing specific substituents (e.g., fluorine atoms, aromatic rings) to change the glass transition temperature from 100°C or lower (NPB) to above 100°C, thereby improving thermal stability for high current applications

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If PEDOT:PSS is used as hole transport material, then solution coating method can be applied, but the LUMO energy level is lower than light emitting layer material making high efficiency and long lifespan difficult to achieve

Engineering Contradiction:
Improvesolution coating capabilityVSAvoiddevice efficiency and lifespan
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent creates hole transport materials with spatially differentiated properties: maintaining solution processability while introducing specific functional groups (aromatic rings, fluorine substituents) at strategic positions to achieve appropriate energy levels (LUMO higher than light emitting layer) for improved device efficiency and lifespan

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent combines multiple functional elements (aromatic rings, fluorine atoms, specific substituents) within a single molecular structure to achieve both solution processability and appropriate energy level alignment, creating a composite functional material that satisfies multiple requirements simultaneously

Inventive Principle:
Principle #40Composite materials

3Reliability

If organic materials are used in light emitting devices, then the devices can operate, but electrochemical stability and interfacial characteristics need improvement for better performance

Engineering Contradiction:
Improveelectrochemical stabilityVSAvoidmaterial structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent systematically modifies molecular parameters (introducing fluorine atoms, aromatic rings, and specific substituents at defined positions) to enhance electrochemical stability and interfacial characteristics, achieving better device performance through controlled structural changes

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 novel compound improves the efficiency and lifespan of organic electronic devices by reducing driving voltage, enhancing light emission efficiency, and ensuring thermal stability, making it suitable for various organic electronic applications.

Implementation Method 1

holes and electrons which are injected into the organic light emitting device must be smoothly transported to a light emitting layer

Methodology Applied
Scientific EffectCharge transport: Conduction (electrical)

Implementation Method 2

electrons and holes are injected from the cathode and the anode into the organic material layer. The electrons and the holes which are injected into the organic material layer are recombined to form an exciton, and the exciton is reduced to a bottom state to emit light

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 3

it is preferable that the material used in the organic light emitting device have excellent thermal stability. The reason is that joule heat is generated by movement of electric charges in the organic light emitting device

Methodology Applied
Scientific EffectThermal stability: Thermal Insulation

Data Source

PatentEP2796448B1Material for organic electronic device and organic electronic device using the same
Publication Date: 2018.04.25 LG CHEM LTD
  • EP2796448B1 patent drawingFigure 1~2
  • EP2796448B1 patent drawingFigure 3
  • EP2796448B1 patent drawingFigure 4

AI summary

The present invention provides a novel compound that is capable of largely improving a life time, efficiency, electrochemical stability, and thermal stability of an organic electronic device, and an organic electronic device that comprises an organic material layer comprising the compound.