OLED Emitter Layer Using Organometallic Dopant and Spiro-Bifluorene Transport

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Solution Overview

Problem

Current organic light emitting diodes (OLEDs) face challenges in achieving high luminous efficiency and long luminous lifespan, particularly due to the short lifespan of phosphorescent materials used in commercial applications.

Innovation Solution

The development of an OLED structure incorporating a specific organometallic compound as a dopant, combined with biscarbazole-based and azine-based hosts, and spiro-bifluorene-based hole transport and benzimidazole-based electron transport layers, which enhances charge and exciton energy transfer, reducing driving voltage and improving luminous efficiency and lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If phosphorescent material is used to achieve high luminous efficiency, then luminous efficiency is improved, but luminous lifespan deteriorates

Engineering Contradiction:

Improveluminous efficiencyVSAvoidluminous lifespan

Core Design Contradiction:

Use of energy by moving objectVSDuration of action of stationary object

Solution Approach 1:

The patent changes the chemical composition parameters of the emitting material layer by using specific organometallic compounds (Formula 1) with particular ligand structures (Formulae 2-4) and controlling dopant concentrations (0.1-20 wt%), which modifies the energy transfer characteristics and extends the operational lifespan while maintaining high luminous efficiency

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material systems combining organometallic dopants with specific host materials (Formulae 7-10) in the emitting layer, and integrates multiple functional layers including hole transport layers (Formula 11) and electron transport layers (Formula 13), creating a synergistic structure that simultaneously achieves high efficiency and long lifespan

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If conventional OLED structure is used, then manufacturing simplicity is maintained, but luminous efficiency and lifespan deteriorate

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidluminous efficiency

Core Design Contradiction:

Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The patent optimizes parameters including dopant concentration (0.1-20 wt%), host-dopant ratios, and layer thicknesses to achieve high luminous efficiency without requiring complex manufacturing processes, maintaining ease of manufacture through conventional OLED fabrication techniques

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies specific material compositions and structures locally in the emitting material layer and transport layers, using organometallic compounds with specific ligand structures in the emitting layer while using different optimized materials in transport layers, allowing each region to perform its function optimally without complicating overall manufacturing

Inventive Principle:

Principle #3Local quality

3Device complexity

If conventional OLED structure is used, then device complexity is minimized, but driving voltage remains high

Engineering Contradiction:

Improvedevice complexityVSAvoiddriving voltage

Core Design Contradiction:

Device complexityVSStress or pressure

Solution Approach 1:

The patent changes the energy level parameters and charge transport properties by selecting specific organometallic compounds and host materials with matched energy levels, which reduces the energy barrier for charge injection and transport, thereby lowering driving voltage without increasing device complexity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces specific hole transport layers (Formula 11) and electron transport layers (Formula 13) as intermediary layers that facilitate efficient charge transport between electrodes and the emitting layer, reducing the voltage required for operation while maintaining a relatively simple overall device structure

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This configuration results in improved luminous efficiency and extended lifespan of OLEDs by facilitating rapid charge and exciton energy transfer, thereby decreasing driving voltage and enhancing overall performance.

Implementation Method 1

an organic light emitting diode that may have improved luminous efficiency and luminous lifespan

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

PatentUS20230171978A1Organic light emitting diode and organic light emitting device having thereof

Publication Date: 2023.06.01 LG DISPLAY CO LTD

AI summary

The present disclosure relates to an organic light emitting diode (OLED) in which at least one emitting material layer includes a dopant having the following structure of Formula 1 and a biscarbazole-based material and/or an azine-based material, at least one hole transport layer includes a spiro-bifluorene-based material and at least one electron transport layer includes a benzimidazole-based material, and an organic light emitting device including the OLED. The OLED and the organic light emitting device including the host and the dopant can improve their luminous efficiency and luminous lifespan.Ir(LA)m(LB)n [Formula 1]