Organic Electronic Device Anode Sub-Layer Voltage Stability

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Solution Overview

Problem

Existing organic electronic devices, such as OLEDs, face challenges in maintaining operating voltage stability over time due to the characteristics of semiconductor materials and metal complexes in their semiconductor layers.

Innovation Solution

Incorporating a compound of formula (I) in the hole injection layer, with specific structural requirements and a layered structure including a first anode sub-layer with a work function between 4 and 6 eV and a second anode sub-layer of transparent conductive oxide, to enhance the balance of hole and electron injection and emission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional semiconductor materials and metal complexes are used in the semiconductor layer, then device structure is simple, but operating voltage stability deteriorates over time

Engineering Contradiction:
Improveoperating voltage stabilityVSAvoidanode layer structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The anode is divided into two separate sub-layers: a first anode sub-layer comprising a first metal with work function ≥4 eV, and a second anode sub-layer comprising a transparent conductive oxide. This segmentation allows each layer to perform its function optimally, improving hole injection and operating voltage stability without requiring complex material modifications

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first anode sub-layer acts as an intermediary between the second anode sub-layer (transparent conductive oxide) and the hole injection layer. This intermediate metal layer with specific work function characteristics facilitates balanced charge injection and improves operating voltage stability over time

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If hole injection is enhanced to improve emission efficiency, then electron-hole balance deteriorates

Engineering Contradiction:
Improveemission efficiencyVSAvoidelectron-hole balance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The first metal in the first anode sub-layer is selected to have a work function in the range of ≥4 eV, which is a specific parameter optimization. This work function value is carefully chosen to balance hole injection efficiency with electron-hole balance, preventing excessive hole injection that would disrupt charge balance

Inventive Principle:
Principle #35Parameter changes

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 leads to superior operating voltage stability and efficiency in organic electroluminescent devices, reducing the impact of semiconductor material characteristics on device performance over time.

Implementation Method 1

the first anode sub-layer comprises a first metal having a work function in the range of ≥ 4 and ≤ 6 eV

Methodology Applied
Scientific EffectWork function:

Implementation Method 2

the second anode sub-layer comprises a transparent conductive oxide

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

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

PatentEP3989301A1Organic electronic device comprising a compound of formula (1), display device comprising the organic electronic device as well as compounds of formula (1) for use in organic electronic devices
Publication Date: 2022.04.27 NOVALED GMBH
  • EP3989301A1 patent drawingFigure 1~2
  • EP3989301A1 patent drawingFigure 3
  • EP3989301A1 patent drawingFigure 4

AI summary

The present invention relates to a compound of formula (i) and an organic electronic device comprising a semiconductor layer which comprises a compound of formula (I).