Fused Polycyclic Compounds for TADF Emission Efficiency and Lifetime

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Solution Overview

Problem

Existing organic electroluminescence devices face challenges in achieving low driving voltage, high emission efficiency, and extended lifetime, particularly in the development of materials for thermally activated delayed fluorescence (TADF) materials.

Innovation Solution

Incorporation of a fused polycyclic compound, represented by specific chemical formulas, in the emission layer of a light emitting element to enhance emission efficiency and element lifetime, utilizing its unique molecular structure to separate HOMO and LUMO states and reduce triplet-singlet energy differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional organic electroluminescence materials are used, then the device can operate, but the emission efficiency and lifetime are insufficient

Engineering Contradiction:

Improveemission efficiencyVSAvoiddevice lifetime

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent modifies molecular parameters of the organic compound by introducing a fused polycyclic core structure with specific heteroatoms (X = O, S, or N(R8)) and substituent groups (R1-R7). These parameter changes in the molecular structure enable simultaneous improvement of emission efficiency and device lifetime by optimizing the electronic properties and stability of the material

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite molecular structure combining a fused polycyclic core with various substituent groups (amine, oxy, thio, alkyl, aryl, heteroaryl groups). This composite structure integrates multiple functional characteristics that collectively enhance both emission efficiency and operational lifetime of the electroluminescence device

Inventive Principle:

Principle #40Composite materials

2Productivity

If triplet excitons are utilized for emission, then emission efficiency can be improved, but triplet-triplet annihilation occurs reducing overall performance

Engineering Contradiction:

Improveemission efficiencyVSAvoidtriplet-triplet annihilation

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent converts the harmful triplet-triplet annihilation process into a beneficial mechanism by designing the molecular structure to facilitate triplet-triplet annihilation fluorescence (TTA-FL). The fused polycyclic structure with specific substituents enables triplet excitons to annihilate and generate singlet excitons that emit fluorescence, transforming energy loss into useful emission and improving overall emission efficiency

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 fused polycyclic compound improves emission efficiency and extends the lifetime of the light emitting element, maintaining high efficiency and color purity while reducing triplet exciton concentration and suppressing triplet-triplet annihilation.

Implementation Method 1

Development is presently directed to a thermally activated delayed fluorescence (TADF) material that utilizes delayed fluorescence phenomenon

Methodology Applied

Scientific EffectThermally activated delayed fluorescence (TADF):

Implementation Method 2

fluorescence emission in which singlet excitons are generated by the collision of triplet excitons (triplet-triplet annihilation, TTA)

Methodology Applied

Scientific EffectTriplet-triplet annihilation (TTA):

Data Source

PatentUS20250221307A1Light emitting element, fused polycyclic compound for the same and display device including the same

Publication Date: 2025.07.03 SAMSUNG DISPLAY CO LTD

AI summary

Embodiments provide a fused polycyclic compound and a light emitting element. The light emitting element includes a first electrode, a second electrode disposed on the first electrode, and an emission layer disposed between the first electrode and the second electrode and including the fused polycyclic compound. The fused polycyclic compound is represented by Formula 1, which is explained in the specification: