OLED Host Material Composition for Solution Processing

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Solution Overview

Problem

Current OLED materials face challenges in achieving high efficiency, long lifetime, and thermal stability, particularly for blue-emitting OLEDs, and require improved host materials for fluorescent emitters that can be easily processed from solutions to form homogeneous films, avoiding layer thickness inhomogeneities that affect luminance distribution.

Innovation Solution

A composition comprising a compound of formula (H1) and a compound of formula (H2), specifically designed to serve as host materials in OLEDs, which are suitable for solution processing and form smooth, homogeneous films, enhancing the performance of OLEDs by improving efficiency, lifetime, and thermal stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional host materials are used in OLEDs, then device structure is simple, but efficiency and lifetime are insufficient

Engineering Contradiction:
ImproveOLED lifetimeVSAvoidhost material structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs composite host materials comprising multiple compounds with different molecular structures (e.g., mCP, TCTA, TAPC combinations) to achieve synergistic effects. This composite approach improves OLED lifetime and efficiency by combining the advantages of individual materials while mitigating their respective limitations, directly resolving the contradiction between reliability improvement and structural complexity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent systematically varies molecular parameters of host materials including weight, structure type, and functional groups to optimize performance. By changing these parameters, the invention achieves improved charge transport properties and exciton management, thereby enhancing OLED lifetime without requiring fundamentally complex material systems.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If complex vapor deposition processes are used, then film quality is high, but manufacturing cost and complexity increase

Engineering Contradiction:
Improvefilm homogeneityVSAvoidprocessing process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical vapor deposition systems with simpler solution-based processing methods. The host materials are designed to be soluble in common solvents, enabling deposition via spin-coating, dip-coating, or inkjet printing. This substitution maintains film homogeneity and quality while dramatically reducing manufacturing complexity and cost.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state parameter of the materials from requiring vapor phase deposition to being processable in solution phase. This parameter change enables the use of simpler, more cost-effective manufacturing processes while maintaining the required film quality through proper solvent selection and processing conditions.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If solution processing is used, then manufacturing is simpler, but film homogeneity and smoothness deteriorate

Engineering Contradiction:
Improveprocessing simplicityVSAvoidfilm smoothness
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent optimizes solution processing parameters including solvent type, concentration, and drying conditions to achieve smooth, homogeneous films. By carefully controlling these parameters, the invention eliminates the typical roughness and inhomogeneity associated with solution processing, maintaining manufacturing simplicity while achieving high film quality.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces local functional groups and molecular structures in the host materials that promote uniform film formation and reduce aggregation. These local structural modifications ensure homogeneous film quality across the entire deposited area, resolving the contradiction between easy manufacturing and film smoothness.

Inventive Principle:
Principle #3Local quality

4Stability of the object's composition

If single host material is used, then material complexity is low, but thermal stability and efficiency are insufficient

Engineering Contradiction:
Improvethermal stabilityVSAvoidhost material composition
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent uses composite host material systems where multiple compounds work synergistically to enhance thermal stability. The combination of materials with different thermal properties creates a more thermally stable overall system, directly addressing the contradiction between improved stability and increased composition complexity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent designs host materials that perform multiple functions simultaneously: charge transport, exciton management, and thermal stability enhancement. This multi-functionality reduces the need for separate specialized materials, thereby improving thermal stability without proportionally increasing system complexity.

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 composition achieves improved efficiency, extended lifetime, and uniform film formation, reducing layer thickness inhomogeneities and enhancing the overall performance and quality of OLEDs, particularly for blue-emitting devices.

Implementation Method 1

electroluminescent materials which have been used in electroluminescent devices to date

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP4118697B1Materials for organic electroluminescent devices
Publication Date: 2024.01.24 MERCK PATENT GMBH
  • EP4118697B1 patent drawingFigure 1~2
  • EP4118697B1 patent drawingFigure 3~4b
  • EP4118697B1 patent drawing

AI summary

The present invention relates to a composition comprising a compound of formula (H1) and a compound of formula (H2). The present invention furthermore relates to a formulation comprising a composition comprising a compound of formula (H1) and a formula (H2) and a solvent. Finally, the present invention relates to an electronic device comprising a such a composition.