Mixed OLED Blocking Layer for Exciton Confinement and Charge Transport

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Solution Overview

Problem

There is a need to address exciton and charge leakage out of the emissive region in organic light emitting diodes (OLEDs) to improve exciton confinement, device efficiency, and operational stability.

Innovation Solution

A mixed blocking layer comprising a blocking material and a transport material is introduced, where the blocking material has a triplet exciton energy greater than the emissive material and specific energy level alignments, and the transport material facilitates efficient charge transport and injection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a blocking layer is introduced to prevent exciton and charge leakage, then exciton confinement and device efficiency are improved, but device complexity increases due to additional layers and material combinations

Engineering Contradiction:

Improveexciton confinementVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines blocking and transport functions into a single mixed blocking layer by blending blocking material and transport material. This merging approach prevents exciton and charge leakage while maintaining charge transport capability, thereby improving exciton confinement and device efficiency without proportionally increasing device complexity compared to multiple separate layers

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent uses composite materials by creating a mixed blocking layer composed of blocking material and transport material in specific ratios. This composite structure provides both blocking and transport properties simultaneously, resolving the contradiction between preventing leakage and maintaining device functionality without requiring multiple separate layers

Inventive Principle:

Principle #40Composite materials

2Reliability

If a blocking layer is introduced to prevent exciton and charge leakage, then operational stability is improved, but device complexity increases due to additional layers and material combinations

Engineering Contradiction:

Improveoperational stabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges blocking and transport functions into a single mixed blocking layer, which prevents exciton and charge leakage to improve operational stability. This approach avoids the need for multiple separate layers that would increase device complexity, achieving stability enhancement with minimal structural addition

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The composite mixed blocking layer combines blocking material and transport material to simultaneously achieve leakage prevention and charge transport. This composite approach improves operational stability without requiring complex multi-layer structures, as the single mixed layer performs multiple functions

Inventive Principle:

Principle #40Composite materials

3Reliability

If blocking material with high triplet exciton energy is used to confine excitons, then exciton confinement is improved, but charge transport capability may be reduced

Engineering Contradiction:

Improveexciton confinementVSAvoidcharge transport capability

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The patent merges blocking material with high triplet exciton energy (for exciton confinement) and transport material (for charge transport) into a single mixed blocking layer. The blocking material prevents exciton leakage while the transport material maintains charge transport capability, resolving the contradiction between exciton confinement and charge transport through functional integration

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The composite mixed blocking layer combines blocking material (providing high triplet exciton energy for exciton confinement) and transport material (providing charge transport capability). The synergistic combination of these materials in specific ratios allows simultaneous achievement of exciton confinement and charge transport without the trade-offs of using either material alone

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 mixed blocking layer enhances exciton confinement, improves device efficiency, and increases operational stability by preventing leakage and reducing degradation of transport layers.

Implementation Method 1

the blocking material has a triplet exciton energy greater than that of the emissive material and specific energy level alignments

Methodology Applied

Scientific EffectEnergy level alignment:

Implementation Method 2

enhances exciton confinement, improves device efficiency

Methodology Applied

Scientific EffectExciton confinement:

Implementation Method 3

the transport material facilitates efficient charge transport and injection

Methodology Applied

Scientific EffectCharge transport: Conduction (electrical)

Implementation Method 4

OLEDs make use of thin organic films that emit light when voltage is applied across the device

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS12382777B2Organic light emitting diode having a mixed blocking layer

Publication Date: 2025.08.05 THE RGT UNIV OF MICHIGAN

AI summary

The present invention relates to mixed blocking layers and devices, such as organic light emitting diodes and other devices, including the same.