Organic Compound Host Material for OLED Lifespan and Efficiency

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Solution Overview

Problem

Current organic optoelectronic devices face challenges in achieving optimal stability, efficiency, and lifespan due to limitations in electron mobility and material interactions, which affect luminous efficiency and color purity in organic light-emitting diodes.

Innovation Solution

A compound with a core structure incorporating carbazolyl and fluorenyl groups linked to N, B, or P atoms, providing hole injection and transport properties, along with electron properties, is developed for use in organic optoelectronic devices, acting as a host material in emission layers to enhance stability and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If conventional organic materials are used in OLEDs, then device structure is simple, but lifespan and thermal stability are insufficient

Engineering Contradiction:
Improvedevice lifespanVSAvoidmaterial structure complexity
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The patent employs composite organic compounds that integrate multiple functional groups (carbazole, fluorene, triphenylamine) within a single molecular structure. This composite approach enables the material to simultaneously provide hole injection, hole transport, and electron transport functions, thereby extending device lifespan and improving thermal stability without requiring multiple separate material layers

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The developed organic compound serves multiple functions within the OLED structure: it acts as a hole injection material, hole transport material, and electron transport material. This multi-functionality reduces the need for separate specialized materials, simplifies device architecture, and improves overall device performance including lifespan and stability

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Productivity

If conventional hole transport materials are used, then hole transport function is provided, but electron mobility and luminous efficiency are limited

Engineering Contradiction:
Improveluminous efficiencyVSAvoidelectron mobility
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent introduces localized electron-donating groups (such as dibenzofuran and dibenzothiophene) at specific positions on the carbazole backbone. This local modification creates regions with enhanced electron mobility without compromising the overall hole transport capability, thereby simultaneously improving both electron mobility and luminous efficiency

Inventive Principle:
Principle #3Local quality

3Use of energy by moving object

If organic materials with high efficiency are used, then luminous efficiency improves, but thermal stability and electrochemical stability deteriorate

Engineering Contradiction:
Improveluminous efficiencyVSAvoidthermal stability
Core Design Contradiction:
Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent systematically adjusts molecular parameters including introducing rigid aromatic groups (dibenzofuran, dibenzothiophene) and optimizing the carbazole-to-fluorene ratio. These parameter changes enhance thermal stability by increasing glass transition temperature and decomposition temperature, while maintaining high luminous efficiency through optimized charge transport properties

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 compound improves the lifespan, efficiency, and thermal stability of organic optoelectronic devices by optimizing hole and electron transport, reducing crystallization, and maintaining high triplet excitation energy, resulting in improved luminous efficiency and prolonged device performance.

Implementation Method 1

The compound has high hole or electron transporting properties

Methodology Applied
Scientific EffectCharge transport: Conduction (electrical)

Implementation Method 2

A second organic optoelectronic device is an electronic device driven as follows: a voltage or a current is applied to at least two electrodes to inject holes and/or electrons into an organic material semiconductor positioned at the interface of the electrodes, and the device are driven by the injected electrons and holes

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 3

maintaining high triplet excitation energy, resulting in improved luminous efficiency

Methodology Applied
Scientific EffectTriplet excitation:

Data Source

PatentEP2421064B1Compound for organic optoelectronic device, organic light emmiting diode including the same and display including the light emmiting diode
Publication Date: 2018.07.04 CHEIL INDUSTRIES INC
  • EP2421064B1 patent drawingFigure 1
  • EP2421064B1 patent drawingFigure 2
  • EP2421064B1 patent drawingFigure 3

AI summary

A compound for an organic optoelectronic device, an organic light emmiting diode, and a display including the organic light emmiting diode are provided. The compound for an organic optoelectronic device is represented by the following Chemical Formula 1 provides an organic optoelectronic device having excellent life-span due to excellent electrochemical and thermal stability, and high luminous efficiency and a low driving voltage.