Fused Polycyclic Compound for OLED Durability and Luminance

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Solution Overview

Problem

Current organic light-emitting devices face challenges with durability, emission luminance, and color purity, particularly in long-term use and exposure to atmospheric gases like oxygen and moisture, and struggle to achieve high conversion efficiency and stable red, green, and blue light emission for full-color displays.

Innovation Solution

A fused polycyclic compound is developed, represented by a specific general formula, which is used in the organic light-emitting device to enhance durability and emission properties, featuring a substituted phenyl group structure that inhibits intermolecular stacking, improving stability and sublimation properties, and is synthesized using a particular route with purification methods to remove impurities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional aromatic compounds or fused ring aromatic compounds are used as constituent materials, then emission luminance can be achieved, but durability deteriorates due to time-dependent change and degradation from atmospheric gases

Engineering Contradiction:
Improveemission luminanceVSAvoiddurability
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent changes the molecular structure parameters by introducing specific fused polycyclic frameworks (triphenylene, pyrene, perylene cores) with particular substitution patterns. This structural parameter change enhances molecular stability and resistance to atmospheric degradation while maintaining emission properties, thereby resolving the contradiction between luminance and durability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates composite molecular structures by combining rigid fused polycyclic cores with various substituent groups (aryl, heterocyclic, amino groups). This composite approach allows the core structure to provide durability while substituents tune emission properties, achieving both high luminance and durability simultaneously

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If conventional aromatic compounds are used, then device production is feasible, but conversion efficiency and color purity for full-color display cannot be sufficiently achieved

Engineering Contradiction:
Improvedevice production feasibilityVSAvoidcolor purity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies local quality by introducing specific functional groups at particular positions on the fused polycyclic core. Different substituents (electron-donating, electron-withdrawing groups) are placed at specific locations to fine-tune HOMO-LUMO energy levels and emission wavelengths, achieving precise color control while maintaining ease of synthesis through conventional organic chemistry methods

Inventive Principle:
Principle #3Local quality

3Illumination intensity

If aromatic compounds with high emission luminance are used, then brightness is improved, but stability deteriorates due to crystallinity and concentration quenching

Engineering Contradiction:
Improveemission luminanceVSAvoidmolecular stability
Core Design Contradiction:
Illumination intensityVSStability of the object's composition

Solution Approach 1:

The patent employs bulky substituent groups (tert-butyl, adamantyl, dendritic groups) that extend into three-dimensional space around the planar fused polycyclic core. This dimensional extension creates steric barriers that prevent intermolecular stacking and aggregation, thereby suppressing concentration quenching and enhancing stability while maintaining high emission luminance through the efficient core structure

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 fused polycyclic compound improves the stability and emission efficiency of organic light-emitting devices by reducing crystallinity, suppressing concentration quenching, and lowering sublimation temperatures, leading to increased device lifespan and improved color purity.

Implementation Method 1

The fused polycyclic compound improves the stability and emission efficiency of organic light-emitting devices by reducing crystallinity

Methodology Applied
Scientific EffectCrystallinity reduction: Crystallisation

Implementation Method 2

featuring a substituted phenyl group structure that inhibits intermolecular stacking, improving stability and sublimation properties

Methodology Applied
Scientific EffectIntermolecular stacking inhibition:

Implementation Method 3

lowering sublimation temperatures

Methodology Applied
Scientific EffectSublimation: Sublimation

Data Source

PatentEP2323963B1Fused polycyclic compound and organic light-emitting device using the compound
Publication Date: 2014.07.23 CANON KK
  • EP2323963B1 patent drawingFigure 1~3
  • EP2323963B1 patent drawingFigure 4~5
  • EP2323963B1 patent drawingFigure 6~7

AI summary

Provided is an organic light-emitting device having good durability. The organic light-emitting device includes an anode, a cathode, and organic compound layers interposed between the anode and the cathode, and at least one of the organic compound layers contains a fused polycyclic compound represented by the following general formula [1]: wherein R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, R17, and R18 each represent, independently of one another, a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, a substituted amino group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, provided that at least one of R1 to R18 is a substituted phenyl group represented by the following general formula [2]:.