Organic Light Emitting Element Stabilizing Organic Layer

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Solution Overview

Problem

Organic light emitting elements face challenges in efficiency and lifespan due to higher hole mobility than electron mobility in the light emitting layer, leading to reduced light emission and stability issues.

Innovation Solution

An organic light emitting element is designed with a compound represented by a specific chemical formula, where X or Y is N or S/O, and R1 and R2 are aryl or heterocyclic groups, to enhance the stability and efficiency of the organic material layer, thereby improving the light emitting properties and lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If phosphorescent organic light emitting element uses conventional light emitting layer materials, then the device can operate, but hole mobility exceeds electron mobility leading to exciton distribution over wide area and reduced light emission efficiency

Engineering Contradiction:
Improvelight emission efficiencyVSAvoidlight emission stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent modifies the chemical structure of the light emitting layer materials by incorporating specific heterocyclic groups (triazine, pyrimidine, pyridine rings) and adjusting molecular weight and glass transition temperature parameters. This changes the mobility balance between holes and electrons, confining excitons to the light emitting layer and improving both efficiency and stability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material systems combining host materials with specific guest dopants (iridium complexes, phosphorescent compounds) in optimized ratios. The host material contains specific functional groups that work synergistically with the dopant to achieve balanced charge transport and improved light emission efficiency

Inventive Principle:
Principle #40Composite materials

2Productivity

If efficiency is increased to improve light emission, then driving voltage decreases, but Joule heating causes crystallization of organic material reducing lifespan

Engineering Contradiction:
Improvelight emission efficiencyVSAvoidelement lifespan
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The patent increases the glass transition temperature (Tg) of the light emitting layer materials above 100°C through molecular structure design. This parameter change raises the thermal stability threshold, preventing crystallization even when Joule heating occurs during high-efficiency operation, thus extending element lifespan

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent preemptively designs materials with high thermal stability margins (Tg > 100°C) to cushion against the harmful effects of Joule heating before it can cause crystallization. This prior cushioning through material selection prevents the degradation pathway before it activates

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Productivity

If conventional host materials with high triplet level are used, then light emitting efficiency improves, but material stability is insufficient leading to reduced lifespan

Engineering Contradiction:
Improvelight emitting efficiencyVSAvoidmaterial stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent modifies host material structures to achieve Tg > 100°C while maintaining high triplet energy levels. This dual parameter optimization ensures both efficient exciton confinement for high light emission and thermal stability to prevent degradation, resolving the contradiction between efficiency and longevity

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 proposed organic light emitting element achieves high efficiency and long lifespan by stabilizing the organic material layer with the specified compound, improving light emission and reducing crystallization from Joule heating.

Implementation Method 1

organic light emission refers to a phenomenon in which electric energy is converted into light energy by an organic material

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

the crystallization of the organic material by the Joule heating during driving is reduced

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4181655A1Organic light emitting element
Publication Date: 2023.05.17 LG DISPLAY CO LTD
  • EP4181655A1 patent drawingFigure 1
  • EP4181655A1 patent drawingFigure 2
  • EP4181655A1 patent drawingFigure 3

AI summary

Embodiments of the disclosure relate to an organic light emitting element (100, 200, 300, 400). Specifically, there may be provided an organic light emitting element (100, 200, 300, 400) having high efficiency or long lifespan by including a first electrode (110), a second electrode (120), and an organic material layer (130) positioned therebetween wherein the organic material layer (130) includes a specific compound.