OLED Electron Transport Compound for Lifetime and Voltage

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Solution Overview

Problem

Current OLED displays face limitations in achieving longer lifetimes while maintaining low operating voltage, particularly for blue OLEDs, and struggle with using the same material in sub-pixels of different colors without compromising efficiency.

Innovation Solution

Incorporating a specific compound as an electron transport material in the OLED layer structure, which enhances the electron transport layer's performance, allowing for longer lifetimes and efficient operation across different color sub-pixels with lower voltage requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If conventional electron transport materials are used in OLED, then the device can operate, but the lifetime is limited and operating voltage remains high

Engineering Contradiction:
ImproveOLED lifetimeVSAvoidoperating voltage
Core Design Contradiction:
Duration of action of stationary objectVSUse of energy by stationary object

Solution Approach 1:

The patent modifies the molecular structure of electron transport materials by introducing specific functional groups (triazine, pyrimidine, pyridine rings with electron-withdrawing substituents) to change the electronic parameters of the material, achieving both lower operating voltage and extended lifetime through optimized electron transport properties

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite electron transport materials combining multiple functional groups and molecular moieties (such as combining triazine rings with specific substituents like fluorine, cyano, or carbonyl groups) to achieve synergistic effects that simultaneously reduce operating voltage and extend device lifetime

Inventive Principle:
Principle #40Composite materials

2Productivity

If different materials are used for different color sub-pixels to optimize efficiency, then performance improves, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidmaterial variety
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent develops universal electron transport materials with broad spectral compatibility that can be used across red, green, and blue sub-pixels without compromising the efficiency of fluorescent emitters, thereby simplifying the manufacturing process while maintaining high performance across all color channels

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

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 use of this compound results in significantly longer pixel lifetimes and improved efficiency for blue OLEDs, enabling the same material to be used in sub-pixels of various colors without jeopardizing performance, particularly for fluorescent emitters.

Implementation Method 1

at least one layer comprising a compound according to generic formula (I) between the cathode and the light emitting layer

Methodology Applied
Scientific EffectElectron transport: Conduction (electrical)

Implementation Method 2

OLEDs emit light after the injection of charge carriers in the form of electrons from the cathode and in form of holes from the anode into organic layers arranged in between. The charge carrier injection is effected on the basis of an applied external voltage, the subsequent formation of excitons in a light emitting zone and the radiative recombination of those excitons.

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3561876B1display
Publication Date: 2022.02.16 NOVALED GMBH
  • EP3561876B1 patent drawingFigure 1~2
  • EP3561876B1 patent drawingFigure 3
  • EP3561876B1 patent drawingFigure 4~5

AI summary

Display comprising at least one organic light emitting diode, wherein the at least one organic light emitting diode comprises an anode, a cathode, a light emitting layer between the anode and the cathode, and at least one layer comprising a compound according to formula (I) between the cathode and the light emitting layer: wherein A1 and A2 are independently selected from halogen, CN, substituted or unsubstituted C1-C20-alkyl or heteroalkyl, C6-C20-aryl or C5-C20-heteroaryl, C1-C20-alkoxy or C6-C20-aryloxy, A3 is selected from substituted or unsubstituted C6-C40-aryl or C5-C40-heteroaryl, m = 0, 1 or 2, n = 0, 1 or 2.