OLED Electron Transport Layer With Silver Cathode Contact

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Solution Overview

Problem

Existing organic electronic devices, particularly tandem OLEDs, face inefficiencies and short lifespan due to imbalanced electron and hole injection, high operating voltage, and power consumption issues, which hinder their application in large-size flat panel displays and mobile devices.

Innovation Solution

An organic electronic device with a cathode comprising silver and/or a silver-containing alloy, and a first electron transport layer containing a phosphine oxide group-based matrix compound, where the electron transport layer is in direct contact with the cathode, enhancing electron mobility and stability while maintaining a constant operating voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional electron transport layers are used in tandem OLEDs, then device structure is simple, but efficiency is low and lifespan is short

Engineering Contradiction:
Improvedevice efficiencyVSAvoidlayer structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent changes the chemical parameters of the electron transport layer by introducing phosphine oxide group-based matrix compounds with specific molecular structures (Formula 1 and Formula 2). This chemical parameter change improves electron mobility and balances charge injection, thereby increasing device efficiency and lifespan without adding structural complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining phosphine oxide group-based matrix compounds with metal salts (such as lithium salts, alkaline earth metal salts, or rare earth metal salts) in the electron transport layer. This composite approach enhances both efficiency and stability while maintaining a relatively simple single-layer structure

Inventive Principle:
Principle #40Composite materials

2Illumination intensity

If higher current density is used to increase brightness, then brightness improves, but operating voltage increases and power consumption rises

Engineering Contradiction:
ImprovebrightnessVSAvoidpower consumption
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent changes the electrical parameters of the device by using phosphine oxide group-based compounds that improve electron mobility and balance charge injection. This allows the device to achieve higher brightness at lower current densities, thereby reducing power consumption while maintaining excellent operating voltage characteristics

Inventive Principle:
Principle #35Parameter changes

3Productivity

If electron mobility is increased to improve efficiency, then efficiency improves, but electrochemical stability may deteriorate

Engineering Contradiction:
Improveelectron mobilityVSAvoidelectrochemical stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent uses composite materials by combining phosphine oxide group-based matrix compounds with metal salts. The phosphine oxide group provides high electron mobility, while the metal salt component enhances electrochemical stability. This composite approach allows simultaneous improvement of both electron mobility and stability

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent introduces specific functional groups (phosphine oxide groups) at local positions within the molecular structure to enhance electron mobility, while the overall molecular framework and metal salt additives provide electrochemical stability. This local quality enhancement allows independent optimization of different properties

Inventive Principle:
Principle #3Local quality

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 solution improves the efficiency and lifespan of organic electronic devices by balancing electron and hole injection, reducing power consumption, and maintaining stable operating voltage, thus enhancing their performance for large-size displays and mobile applications.

Implementation Method 1

the first electron transport layer comprises a first electron transport matrix compound and a metal salt; the first electron transport matrix compound comprises a phosphine oxide group

Methodology Applied
Scientific EffectElectron transport: Conduction (electrical)

Implementation Method 2

the cathode comprises silver and/or a silver-containing alloy; the first electron transport layer is in direct contact with the cathode

Methodology Applied
Scientific EffectElectron injection: Thermionic Emission

Implementation Method 3

When the excitons drop from an excited state to a ground state, light is emitted

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP4312281A1Organic electronic device and display device comprising the same
Publication Date: 2024.01.31 NOVALED GMBH
  • EP4312281A1 patent drawingFigure 1~2
  • EP4312281A1 patent drawingFigure 3
  • EP4312281A1 patent drawingFigure 4

AI summary

The present invention relates to an organic electronic device comprising an anode, a cathode, a first emission layer and a first electron transport layer, wherein - the first emission layer is arranged between the anode and the cathode;- the first electron transport layer is arranged between first emission layer and the cathode;- the first electron transport layer comprises a first electron transport matrix compound and a metal salt;- the first electron transport matrix compound comprises a phosphine oxide group;- the cathode comprises silver and/or a silvercontaining alloy; and- the first electron transport layer is in direct contact with the cathode; and to a display device comprising the organic electronic device.