OLED Electron Transport Layer Compound for Stability and Mobility

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Solution Overview

Problem

Existing organic light-emitting diodes (OLEDs) face challenges in achieving balanced electron and hole injection, which affects their efficiency and lifetime, particularly for large-size flat panel displays, due to limitations in electron mobility and electrochemical stability of organic semiconductor layers.

Innovation Solution

An OLED structure incorporating a non-transparent substrate, an anode, a cathode, an emission layer, and an electron transport layer stack, where the electron transport layer stack includes a second electron transport layer composed of a specific compound (Ar2m-(Zk-G)n without electrical dopants, enhancing electron mobility and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional organic semiconductor materials are used in the electron transport layer, then the device structure can be maintained, but electron mobility remains insufficient and electrochemical stability is poor

Engineering Contradiction:
Improveelectrochemical stabilityVSAvoidelectron mobility
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent modifies the chemical structure of organic semiconductor materials by introducing specific molecular groups and optimizing structural parameters to simultaneously achieve high electron mobility and electrochemical stability. The compound formula (II) with specific structural features enables both improved charge transport and enhanced stability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The electron transport layer is constructed using composite organic semiconductor materials that combine different molecular components to achieve synergistic effects. The specific compound structure integrates multiple functional moieties that collectively provide both high electron mobility and electrochemical stability.

Inventive Principle:
Principle #40Composite materials

2Productivity

If the organic semiconductor layer characteristics are not optimized, then the manufacturing process remains simple, but driving voltage is high and efficiency is low

Engineering Contradiction:
Improvedevice efficiencyVSAvoiddriving voltage
Core Design Contradiction:
ProductivityVSPower

Solution Approach 1:

The patent optimizes key parameters of the organic semiconductor materials, including HOMO-LUMO energy levels, molecular packing density, and charge carrier mobility, to reduce driving voltage and improve device efficiency. The specific compound structure enables better charge injection and transport, leading to lower operating voltages and higher efficiency.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If electron mobility is increased without optimizing electrochemical stability, then charge transport improves, but device lifetime decreases

Engineering Contradiction:
Improveelectron mobilityVSAvoiddevice lifetime
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The patent achieves high electron mobility while maintaining electrochemical stability by carefully designing the molecular structure with appropriate energy levels, steric protection, and chemical stability features. The compound formula (II) incorporates structural elements that protect against degradation while facilitating charge transport.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The organic semiconductor material is designed as a composite structure combining high-mobility moieties with stability-enhancing groups, creating a material that simultaneously provides excellent charge transport and long-term electrochemical stability for extended device lifetime.

Inventive Principle:
Principle #40Composite materials

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 structure improves driving voltage and efficiency by utilizing a compound in the second electron transport layer that enhances electron mobility and electrochemical stability, leading to improved performance in OLEDs, especially for large-size flat panel displays.

Implementation Method 1

the second electron transport layer consists of a compound of formula (II) enhancing electron mobility

Methodology Applied
Scientific EffectElectron transport: Conduction (electrical)

Implementation Method 2

The holes and electrons recombine in the EML to generate excitons. When the excitons drop from an excited state to a ground state, light is emitted.

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP4391765A1Organic light emitting diode, display device comprising the same and compound
Publication Date: 2024.06.26 NOVALED GMBH
  • EP4391765A1 patent drawingFigure 1
  • EP4391765A1 patent drawingFigure 2
  • EP4391765A1 patent drawingFigure 3

AI summary

The present invention relates to an organic light emitting diode and a display device comprising the same. The invention further relates to a compound which can be used in the organic light emitting diode.