Triarylmonoamine Dopant in Blue OLED Emitter

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Solution Overview

Problem

Current organic electroluminescent devices (OLEDs), particularly blue-emitting ones, face challenges in achieving high efficiency and long lifetime, with existing solutions not fully satisfying performance requirements.

Innovation Solution

Incorporating a triarylmonoamine as a dopant in the emitting layer, combined with a matrix material containing an anthracene or pyrene unit, to enhance efficiency and lifetime while maintaining high color purity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single compound is used in the emitting layer, then the device structure is simple, but the efficiency and lifetime are insufficient

Engineering Contradiction:

Improvedevice lifetimeVSAvoidemitting layer composition

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a composite emitting layer comprising three specific compounds: a first compound (e.g., mCP), a second compound (e.g., TCTA), and a third compound (e.g., TAPC). This composite material approach enables simultaneous achievement of high efficiency and long lifetime in blue fluorescent OLEDs, resolving the contradiction between simple structure and high performance.

Inventive Principle:

Principle #40Composite materials

2Reliability

If multiple compounds are used in the emitting layer, then efficiency increases, but the device complexity increases

Engineering Contradiction:

Improvedevice efficiencyVSAvoidemitting layer composition

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent optimizes the specific parameters of the emitting layer by selecting compounds with particular molecular weights, HOMO/LUMO energy levels, and steric properties. The first compound has molecular weight 150-300 Da, the second has 200-400 Da with specific HOMO level range, and the third has 200-400 Da with specific steric properties. These parameter optimizations enable high efficiency while controlling complexity through precise material selection criteria.

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If conventional dopant and matrix combinations are used, then the emitting layer is simple to prepare, but power efficiency and lifetime are insufficient

Engineering Contradiction:

Improvepower efficiencyVSAvoidemitting layer preparation

Core Design Contradiction:

Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent employs conventional OLED manufacturing techniques including vacuum thermal evaporation and solution processing methods. The emitting layer can be deposited using standard equipment and procedures, making the high-performance tri-compound system economically viable despite the increased material complexity.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 triarylmonoamines with anthracene or pyrene units in the emitting layer results in improved power efficiency, extended operating lifetime, and high color purity, particularly for blue emission.

Implementation Method 1

the term OLED is taken to mean electronic devices which comprise organic material and emit light on application of an electrical voltage

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS11631816B2Electronic device

Publication Date: 2023.04.18 IDEMITSU KOSAN CO LTD

AI summary

The present application relates to an electronic device having defined composition of the emitting layer. The application furthermore relates to the use of the device in displays or in lighting applications.