Organic TADF Emitters for Stable Blue-Green OLED Efficiency

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Solution Overview

Problem

Existing optoelectronic devices, particularly organic light-emitting diodes (OLEDs), face challenges in achieving high efficiency and stability, especially in blue, sky-blue, or green spectral ranges, with existing emitter materials lacking in thermally activated delayed fluorescence (TADF) and exhibiting lower photoluminescence quantum yields.

Innovation Solution

Development of purely organic molecules with specific structural formulas (Illaa, Illab, Illac) that exhibit TADF, high photoluminescence quantum yields (>26%), and improved stability, which can be used in combination with fluorescence emitters to enhance device efficiency and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal complexes are used as emitter materials in OLEDs, then photoluminescence quantum yields can be achieved, but device stability and efficiency remain insufficient

Engineering Contradiction:

Improvedevice stabilityVSAvoidefficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent removes metal ions from the emitter material structure, extracting the harmful element that causes stability issues while maintaining the photoluminescence function through purely organic molecular structures with specific donor-acceptor configurations

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention employs composite molecular structures combining electron-donating moieties and electron-accepting moieties in specific configurations to achieve both high photoluminescence quantum yields and thermal activated delayed fluorescence, resolving the contradiction between efficiency and stability

Inventive Principle:

Principle #40Composite materials

2Loss of energy

If metal complexes are used to achieve high photoluminescence quantum yields, then emission performance improves, but device lifetime and stability deteriorate

Engineering Contradiction:

Improvephotoluminescence quantum yieldVSAvoiddevice lifetime

Core Design Contradiction:

Loss of energyVSDuration of action of stationary object

Solution Approach 1:

The patent extracts metal ions from the emitter material, eliminating the source of degradation while preserving the photoluminescence quantum yield through carefully designed organic molecular structures with optimized donor-acceptor interactions

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the fundamental parameter of emitter composition from metal-containing complexes to purely organic structures, fundamentally altering the degradation pathway and extending device lifetime while maintaining high photoluminescence quantum yields

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If conventional organic emitters are used, then device simplicity is maintained, but photoluminescence quantum yields and thermal activated delayed fluorescence are insufficient

Engineering Contradiction:

Improveemitter structure simplicityVSAvoidphotoluminescence quantum yield

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent divides the emitter molecule into distinct electron-donating and electron-accepting moieties connected through specific linkers, creating a segmented architecture that enables both high photoluminescence quantum yields and thermal activated delayed fluorescence while maintaining synthetic accessibility

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention creates composite molecular structures by combining specific donor units, acceptor units, and linker groups, achieving enhanced photoluminescence performance through molecular-level composition without requiring complex device architectures

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 organic molecules provide higher efficiency and stability in OLEDs, enabling hyperfluorescence and improved performance in blue, sky-blue, or green spectral ranges, with emission peaks in the visible or nearest ultraviolet range and excited state lifetimes under 150 µs.

Implementation Method 1

The organic molecules exhibit in particular thermally activated delayed fluorescence (TADF)

Methodology Applied

Scientific EffectThermally activated delayed fluorescence (TADF): Fluorescence

Implementation Method 2

The organic molecules exhibit emission maxima in the blue, sky-blue or green spectral range. The photoluminescence quantum yields of the organic molecules according to the invention are, in particular, 26 % or more

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP3670507B1Organic molecules for use in optoelectronic devices

Publication Date: 2026.05.06 SAMSUNG DISPLAY CO LTD

Figure 1

AI summary

The invention relates to a light emitting organic molecule, in particular for the application in optoelectronic devices. According to the invention, the organic molecule has - one first chemical moiety with a structure of formula I, and - two second chemical moieties with a structure of formula II, Wherein # represents the binding site of a single bond linking the first chemical moiety to the second chemical moiety; one of W, X and Y is benzonitryl and one of W', X' and Y' is benzonitryl one of W, V and T is the bond linking the first chemical moiety to one of the two second chemical moieties; and one of W', V' and T' is the bond linking the first chemical moiety to one of the two second chemical moieties.