Polycyclic Aromatic Compound for Blue OLED Host Materials

Solution Overview

Problem

Current organic electroluminescent elements lack materials with high triplet excitation energy and sufficient redox stability for use as host materials, particularly for blue light emission and thermally activated delayed fluorescence applications.

Innovation Solution

A novel polycyclic aromatic compound with aromatic rings linked via boron, nitrogen, or other heteroatoms is developed, providing a large HOMO-LUMO gap and high triplet excitation energy, suitable for use in organic electroluminescent elements as a material for light emitting, electron transport, or hole transport layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polycyclic aromatic compounds with extended n-conjugated systems are used, then redox stability is improved, but HOMO-LUMO gap and triplet excitation energy become too low for host material applications

Engineering Contradiction:

Improveredox stabilityVSAvoidHOMO-LUMO gap and triplet excitation energy

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The molecule is divided into two functional segments: a polycyclic aromatic hydrocarbon core (providing redox stability) and a heteroatom-containing aromatic ring (providing high triplet excitation energy). This segmentation allows each part to fulfill its specific function without compromising the other, resolving the contradiction between redox stability and energy gap requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention creates a composite molecular structure by linking a polycyclic aromatic hydrocarbon (such as pyrene, perylene, or dibenzofuran) with a heteroatom-containing aromatic ring (such as pyridine, pyrimidine, or triazine) through a connecting group. This composite structure combines the beneficial properties of both components: the polycyclic core provides redox stability while the heteroatom ring provides high triplet excitation energy suitable for host materials.

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If aromatic rings with small conjugated systems are used to increase triplet excitation energy, then T1 energy is improved, but redox stability becomes insufficient for practical applications

Engineering Contradiction:

Improvetriplet excitation energyVSAvoidredox stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The molecule is divided into two functional segments: a polycyclic aromatic hydrocarbon core (providing redox stability) and a heteroatom-containing aromatic ring (providing high triplet excitation energy). This segmentation allows each part to fulfill its specific function without compromising the other, resolving the contradiction between redox stability and energy gap requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention creates a composite molecular structure by linking a polycyclic aromatic hydrocarbon (such as pyrene, perylene, or dibenzofuran) with a heteroatom-containing aromatic ring (such as pyridine, pyrimidine, or triazine) through a connecting group. This composite structure combines the beneficial properties of both components: the polycyclic core provides redox stability while the heteroatom ring provides high triplet excitation energy suitable for host materials.

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 polycyclic aromatic compound enhances the performance of organic electroluminescent elements by improving triplet excitation energy and redox stability, enabling efficient blue light emission and thermally activated delayed fluorescence, while allowing for optimization of ionization potential and electron affinity through substituent introduction.

Implementation Method 1

since a compound having a conjugated structure involving higher energy of triplet exciton (T1) can emit phosphorescent light having a shorter wavelength

Methodology Applied

Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 2

enabling efficient blue light emission and thermally activated delayed fluorescence

Methodology Applied

Scientific EffectThermally activated delayed fluorescence:

Data Source

PatentUS11653565B2Polycyclic aromatic compound

Publication Date: 2023.05.16 SK MATERIALS JNC CO LTD

AI summary

By providing a novel polycyclic aromatic compound in which a plurality of aromatic rings are linked via a boron atom, a nitrogen atom, or the like, options of a material for an organic EL element are increased. In addition, by using the novel polycyclic aromatic compound as a material for an organic electroluminescent element, an excellent organic EL element is provided.