Fused Polycyclic Boron Nitrogen Compound OLED Emission Efficiency

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Solution Overview

Problem

Current organic electroluminescence devices face challenges in reducing driving voltage, increasing emission efficiency, and extending lifespan, particularly in achieving high efficiency through techniques like phosphorescence, delayed fluorescence, and thermally activated delayed fluorescence (TADF) material development.

Innovation Solution

Incorporating a fused polycyclic compound with a specific structure, including a fused polycyclic heterocycle with five rings, one boron atom, two nitrogen atoms, an amine group, and aromatic hydrocarbon rings connected via heteroatoms, into the organic electroluminescence device's emission layer to enhance emission efficiency by reducing the difference between singlet and triplet excitation energy levels, facilitating reverse intersystem crossing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If phosphorescence or delayed fluorescence techniques are used to improve emission efficiency, then emission efficiency is improved, but device complexity and material development difficulty increase

Engineering Contradiction:

Improveemission efficiencyVSAvoidmaterial development complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent modifies molecular parameters by incorporating a fused polycyclic heterocycle with specific heteroatom composition (one boron atom and two nitrogen atoms) and controlled ring fusion patterns. This changes the electronic structure parameters to reduce the singlet-triplet energy gap, enabling efficient delayed fluorescence without requiring complex device structures or multiple dopant systems.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite molecular structure by fusing multiple polycyclic rings with specific heteroatoms (boron, nitrogen, oxygen, sulfur) in defined configurations. This composite approach allows tuning of photophysical properties while maintaining structural simplicity, achieving high emission efficiency through molecular design rather than complex device architecture.

Inventive Principle:

Principle #40Composite materials

2Reliability

If conventional organic compounds are used in the emission layer, then device structure is simpler, but emission efficiency and lifespan are insufficient

Engineering Contradiction:

Improvedevice lifespanVSAvoidcompound structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces specific local structural features within the emission layer compound: a fused polycyclic heterocycle containing exactly one boron atom and two nitrogen atoms, with amine groups positioned at specific locations. These localized structural modifications enhance molecular stability and photophysical performance, extending device lifespan without requiring complete structural redesign of the entire device.

Inventive Principle:

Principle #3Local quality

3Productivity

If the difference between singlet and triplet excitation energy levels is large, then molecular stability is maintained, but reverse intersystem crossing is suppressed and emission efficiency decreases

Engineering Contradiction:

Improveemission efficiencyVSAvoidenergy level stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The patent precisely adjusts the energy level parameters by incorporating heteroatoms (boron, nitrogen, oxygen, sulfur) in specific configurations within the fused polycyclic structure. This modifies the HOMO-LUMO gap and singlet-triplet energy difference to an optimal range that enables efficient reverse intersystem crossing while maintaining molecular stability through aromaticity and delocalization.

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 use of the fused polycyclic compound in the organic electroluminescence device leads to improved emission efficiency, particularly in the blue light wavelength region, with increased maximum external quantum efficiency and external quantum efficiency at high luminance, outperforming comparative examples.

Implementation Method 1

facilitating reverse intersystem crossing

Methodology Applied

Scientific EffectReverse intersystem crossing:

Implementation Method 2

the emission layer may emit delayed fluorescence

Methodology Applied

Scientific EffectDelayed fluorescence:

Data Source

PatentUS11653561B2Organic electroluminescence device and fused polycyclic compound for organic electroluminescence device

Publication Date: 2023.05.16 SAMSUNG DISPLAY CO LTD

AI summary

An organic electroluminescence device of the 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 organic layers includes a fused polycyclic compound represented by Formula 1 below, thereby showing improved emission efficiency and long life:Formula 1