Fused Polycyclic Compound for Delayed-Fluorescence Emission

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Solution Overview

Problem

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

Innovation Solution

Incorporation of a fused polycyclic compound in the organic layers of the light emitting device, specifically in the emission layer, to enhance delayed fluorescence and improve emission efficiency, utilizing a structure defined by specific chemical formulas and substituents to optimize triplet excitation energy levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional organic electroluminescence materials are used, then the device structure is simple, but the emission efficiency is low and triplet state energy is wasted

Engineering Contradiction:

Improvedevice structure simplicityVSAvoidtriplet state energy waste

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent introduces a host-guest system where the host material acts as an intermediary to facilitate triplet-triplet annihilation. The host absorbs triplet excitons from the guest material and mediates the energy transfer process, enabling delayed fluorescence emission while maintaining structural simplicity. This resolves the contradiction by using the host as a mediator to convert wasted triplet energy into useful light emission.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent optimizes key parameters including the triplet energy level matching between host and guest materials, the concentration ratio of host to guest, and the HOMO-LUMO energy level alignment. By carefully controlling these parameters, the device achieves high emission efficiency through delayed fluorescence while maintaining a relatively simple organic electroluminescence structure.

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If phosphorescence emission techniques are used to improve efficiency, then triplet state energy utilization increases, but the device complexity and material development difficulty increase

Engineering Contradiction:

Improvetriplet state energy utilizationVSAvoidmaterial development complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent employs delayed fluorescence emission with microsecond to millisecond lifetimes, which is much shorter than phosphorescence lifetimes. This allows the use of simpler organic materials without requiring heavy metal complexes or special phosphorescent dopants, thereby reducing material development complexity while still achieving high triplet state energy utilization through the delayed fluorescence mechanism.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The host-guest system is designed to be self-sufficient, where the host material automatically mediates the triplet-triplet annihilation process without requiring additional phosphorescent materials or complex device structures. The system self-regulates the energy transfer and emission processes, eliminating the need for complex phosphorescence emission techniques while maintaining high efficiency.

Inventive Principle:

Principle #25Self-service

3Loss of energy

If high emission efficiency is achieved through advanced materials, then energy utilization improves, but the driving voltage increases

Engineering Contradiction:

Improveenergy utilization efficiencyVSAvoiddriving voltage

Core Design Contradiction:

Loss of energyVSStress or pressure

Solution Approach 1:

The patent optimizes the energy levels locally at the emission layer interface by carefully selecting host and guest materials with matched HOMO-LUMO levels and triplet energies. This local optimization ensures efficient charge injection and energy transfer at the emission layer without requiring high driving voltages across the entire device, thereby achieving high energy utilization with moderate voltage operation.

Inventive Principle:

Principle #3Local quality

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 enhances the emission efficiency of the light emitting device, potentially reducing driving voltage and increasing the device's lifespan.

Implementation Method 1

delayed fluorescence emission (which uses the generating phenomenon of singlet excitons by the collision of triplet excitons (triplet-triplet annihilation, TTA))

Methodology Applied

Scientific EffectDelayed fluorescence: Fluorescence

Implementation Method 2

the generating phenomenon of singlet excitons by the collision of triplet excitons (triplet-triplet annihilation, TTA)

Methodology Applied

Scientific EffectTriplet-triplet annihilation:

Implementation Method 3

holes and electrons injected from a first electrode and a second electrode recombine in an emission layer, and a light-emitting material including an organic compound in the emission layer emits light

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS12439821B2Light emitting device and fused polycyclic compound for light emitting device

Publication Date: 2025.10.07 SAMSUNG DISPLAY CO LTD

AI summary

An light emitting device of the present embodiments includes oppositely disposed first electrode and second electrode, and a plurality of organic layers disposed between the first electrode and the second electrode, wherein at least one among the plurality of organic layers includes a fused polycyclic compound represented by Formula 1 below, thereby showing improved emission efficiency: