OLED Red Emitter Material Enhancing Exciton Utilization

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Solution Overview

Problem

Current organic light emitting diodes (OLEDs) face challenges in achieving high luminous efficiency and lifespan due to limitations in exciton generation efficiency and energy transfer in the host and dopant materials, particularly with fluorescent materials showing low efficiency and metal complexes having short lifespan.

Innovation Solution

An OLED structure incorporating a red emitting material layer with specific compounds, including a first compound represented by Formula 1-1, a second compound, and a third compound, which are optimized to enhance luminous efficiency and lifespan by improving exciton utilization and energy transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If fluorescent material is used as dopant, then the OLED structure is simple, but luminous efficiency is low due to only utilizing singlet exciton energy

Engineering Contradiction:
ImproveOLED structure complexityVSAvoidluminous efficiency
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent employs a composite emitting material layer comprising both fluorescent and phosphorescent dopants within the same host matrix. This composite approach enables simultaneous utilization of singlet excitons (via fluorescent material) and triplet excitons (via phosphorescent material), thereby significantly improving luminous efficiency while maintaining a relatively simple single-layer structure.

Inventive Principle:
Principle #40Composite materials

2Loss of energy

If phosphorescent metal complex is used as dopant, then luminous efficiency is high by utilizing triplet exciton energy, but luminous lifespan is short for commercial use

Engineering Contradiction:
Improveluminous efficiencyVSAvoidluminous lifespan
Core Design Contradiction:
Loss of energyVSDuration of action of stationary object

Solution Approach 1:

The patent modifies the molecular structure and concentration parameters of the phosphorescent dopant to optimize performance. By carefully controlling the dopant concentration and selecting specific phosphorescent materials with appropriate lifetimes, the system achieves high luminous efficiency while extending operational stability and lifespan for commercial applications.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The composite emitting layer combines phosphorescent dopant with fluorescent material and host matrix, where the phosphorescent component provides high efficiency through triplet exciton utilization while the fluorescent and host components contribute to enhanced stability and extended lifespan, creating a balanced performance profile.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If conventional host and dopant materials are used, then the OLED manufacturing is simple, but exciton generation efficiency and energy transfer efficiency are insufficient

Engineering Contradiction:
ImproveOLED manufacturing simplicityVSAvoidexciton generation efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent optimizes the energy levels, concentrations, and molecular structures of host and dopant materials to maximize exciton generation efficiency and energy transfer efficiency. By adjusting these material parameters, the system achieves high efficiency while maintaining compatibility with conventional manufacturing 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 proposed OLED design achieves improved luminous efficiency and extended lifespan by utilizing a tailored emitting material layer with specific compounds that enhance exciton utilization and energy transfer, leading to better performance compared to traditional OLEDs.

Implementation Method 1

An organic light emitting diode (OLED) display among a flat display device used widely has come into the spotlight as a display device replacing rapidly a liquid crystal display device (LCD)

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

phosphorescent material can show high luminous efficiency since it uses triplet exciton energy as well as singlet exciton energy in the luminous process

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Data Source

PatentEP4164364B1Organic light emitting diode and organic light emitting device including the same
Publication Date: 2024.05.01 LG DISPLAY CO LTD
  • EP4164364B1 patent drawingFigure 1
  • EP4164364B1 patent drawingFigure 2
  • EP4164364B1 patent drawingFigure 3

AI summary

An organic light emitting diode (D, D1, D2, D3 D4, D5) and an organic light emitting device (100, 300) including the same are discussed. The organic light emitting diode (D, D1, D2, D3 D4, D5) can include a first compound (232, 412, 512, 612, 722) represented by a following formula, a second compound (234, 414, 514, 614, 724) as a p-type host, and a third compound (236, 416, 516, 616, 726) as an n-type host in an emitting material layer. As a result, the organic light emitting diode (D, D1, D2, D3, D4, D5) and the organic light emitting device (100, 300) have advantages in the driving voltage, the luminous efficiency and the lifespan.