Blue OLED Emission Layer Balancing Narrow FWHM and Efficiency

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing organic electroluminescent devices struggle to achieve a balance of high efficiency, long lifetime, and good color purity, particularly in achieving the blue BT-2020 and DCPI3 color gamut, due to broad emission spectra and the use of expensive transition metal-based phosphorescence materials.

Innovation Solution

An organic electroluminescent device comprising a light-emitting layer with a TADF material, an excitation energy transfer component, a small FWHM emitter, and a host material, which together enable efficient energy transfer and narrow emission, suitable for achieving the blue BT-2020 and DCPI3 color gamut.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If phosphorescence materials based on transition metals are used, then high efficiency is achieved, but cost increases due to expensive materials

Engineering Contradiction:

ImproveefficiencyVSAvoidcost

Core Design Contradiction:

Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent replaces expensive transition metal-based phosphorescence materials with organic fluorescence or TADF materials that are cheaper and more abundant, accepting that these materials have shorter operational lifetimes but can be compensated through device design

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the material composition parameters by using organic compounds with specific molecular structures (fluorescence or TADF materials) that exhibit narrow emission spectra, thereby achieving both cost reduction and improved color purity for BT-2020 and DCPI3 color gamut

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If fluorescence or TADF emitters with narrow emission spectrum are used, then color purity is improved, but efficiency decreases due to roll-off behaviour

Engineering Contradiction:

Improvecolor purityVSAvoidefficiency

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent employs composite light-emitting layers combining multiple organic materials (host materials, fluorescence/TADF emitters, and energy transfer components) to achieve synergistic effects that maintain narrow emission spectra while improving efficiency and reducing roll-off behavior

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent introduces energy transfer components as intermediaries that receive energy from excitons and transfer it to fluorescence/TADF emitters, thereby improving efficiency while maintaining the narrow emission spectrum characteristic of organic materials

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If fluorescence or TADF emitters are used, then cost is reduced, but lifetime decreases due to exciton-polaron annihilation

Engineering Contradiction:

ImprovecostVSAvoidlifetime

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent uses composite light-emitting layers with specifically designed host-guest systems where host materials provide stable exciton generation and TADF/fluorescence emitters provide narrow emission, achieving both cost reduction and improved lifetime through material synergy

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes molecular structure parameters of organic materials, including HOMO-LUMO energy level alignments and spatial separation of electrons and holes, to reduce exciton-polaron annihilation and extend device lifetime while maintaining cost advantages

Inventive Principle:

Principle #35Parameter changes

4Use of energy by moving object

If broad emission spectrum is used, then efficiency is improved, but color purity worsens making it difficult to achieve BT-2020 and DCPI3 color gamut

Engineering Contradiction:

ImproveefficiencyVSAvoidcolor purity

Core Design Contradiction:

Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent fundamentally changes the emission spectrum parameter by selecting organic fluorescence or TADF materials with inherently narrow emission spectra (FWHM < 0.25 eV), enabling achievement of BT-2020 and DCPI3 color gamut while maintaining good efficiency through optimized energy transfer

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

The device achieves a long lifetime, high quantum yield, and narrow emission, effectively addressing the balance of efficiency and color purity in organic electroluminescent devices.

Implementation Method 1

The TADF material may for example be a material displaying reversed-intersystem crossing (RISC)

Methodology Applied

Scientific EffectReverse intersystem crossing (RISC):

Implementation Method 2

The latter rely on the use of an energy pump which transfers energy to a fluorescent emitter

Methodology Applied

Scientific EffectEnergy transfer:

Implementation Method 3

a fluorescent emitter preferably displaying a narrow emission spectrum

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP4214773B1Organic electroluminescent device emitting blue light

Publication Date: 2025.12.17 SAMSUNG DISPLAY CO LTD

AI summary

The present invention relates to organic electroluminescent devices comprising a light-emitting layers B comprising a TADF material, an excitation energy transfer component EET-2, a small full width at half maximum (FWHM) emitter SB emitting blue light with an FWHM of less than or equal to 0.25 eV, and a host material HB. Furthermore, the present invention relates to a method for generating blue light by means of an organic electroluminescent device according to the present invention.