OLED Electron Transport Layer Homogeneity for Voltage Reduction

Solution Overview

Problem

Organic light emitting display devices face challenges with high operating voltage and reduced efficiency and lifetime due to barriers in electron injection between the electron transport layer and the emitting layer, primarily caused by different structures of electron-type host materials in these layers.

Innovation Solution

Incorporating heteroaromatic ring compounds with the same core structure as both the electron-type host and electron transport layers to facilitate electron transport, thereby reducing the electron injection barrier and improving the efficiency and lifetime of the device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If different electron-type host materials are used in the electron transport layer and emitting layer, then the device can be formed with standard layered structure, but the electron injection barrier becomes too large causing high operating voltage and reduced efficiency

Engineering Contradiction:

Improvelayered structure formationVSAvoidelectron injection efficiency

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent uses the same electron-type host material (compound of formula 1) in both the electron transport layer and emitting layer to ensure structural homogeneity. This eliminates the electron injection barrier caused by material mismatch while maintaining the standard layered OLED structure for ease of manufacture.

Inventive Principle:

Principle #33Homogeneity

Solution Approach 2:

The electron transport layer acts as an intermediary between the cathode and emitting layer, using the same host material structure to facilitate smooth electron transport. This intermediary layer with matched structure reduces the injection barrier and improves electron injection efficiency into the emitting layer.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If different electron-type host materials are used in the electron transport layer and emitting layer, then the device can be formed with standard layered structure, but the operating voltage increases

Engineering Contradiction:

Improvelayered structure formationVSAvoidoperating voltage

Core Design Contradiction:

Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The patent uses the same electron-type host material (compound of formula 1) in both the electron transport layer and emitting layer to ensure structural homogeneity. This eliminates the electron injection barrier caused by material mismatch while maintaining the standard layered OLED structure for ease of manufacture.

Inventive Principle:

Principle #33Homogeneity

3Ease of manufacture

If different electron-type host materials are used in the electron transport layer and emitting layer, then the device can be formed with standard layered structure, but the lifetime decreases

Engineering Contradiction:

Improvelayered structure formationVSAvoiddevice lifetime

Core Design Contradiction:

Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The patent uses the same electron-type host material (compound of formula 1) in both the electron transport layer and emitting layer to ensure structural homogeneity. This eliminates the electron injection barrier caused by material mismatch while maintaining the standard layered OLED structure for ease of manufacture.

Inventive Principle:

Principle #33Homogeneity

Solution Approach 2:

The electron transport layer acts as an intermediary between the cathode and emitting layer, using the same host material structure to facilitate smooth electron transport. This intermediary layer with matched structure reduces the injection barrier and improves electron injection efficiency into the emitting layer.

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 approach significantly reduces the operating voltage, enhances external quantum efficiency, and increases the lifetime of the organic light emitting display device by ensuring efficient electron transport and stability within the emitting layer.

Implementation Method 1

at least one among the first and second electron transport layers includes a compound represented by the following Chemical Formula 2 or Chemical Formula 3... to facilitate electron transport, thereby reducing the electron injection barrier

Methodology Applied

Scientific EffectElectron transport: Conduction (electrical)

Implementation Method 2

An exciton is formed by the recombination of electrons and holes injected from the two electrodes, causing luminescent materials to emit fluorescent or phosphorescent light

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3032605B1Organic light emitting display device

Publication Date: 2019.08.21 LG DISPLAY CO LTD

Figure 1~2
Figure 3

AI summary

An organic light emitting display device is disclosed. The organic light emitting display device comprises an emitting layer over an anode, the light emitting part having an emitting layer and an electron transporting layer, and a cathode on the light emitting part, wherein each of the emitting layer and the electron transporting layer includes a compound with the same core to facilitate electron transport from the electron transporting layer to the emitting layer.