Condensed Cyclic Emitters for Blue TADF OLED Efficiency

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Solution Overview

Problem

Current organic electroluminescence devices face challenges in achieving low driving voltage, high luminous efficiency, and long service life, necessitating the development of advanced materials for improved performance.

Innovation Solution

A condensed cyclic compound, represented by specific formulas, is used as a luminescent material in the emission layer of an organic electroluminescence device, incorporating heterocycles and benzoazaborine or dibenzoazaborine rings to enhance luminous efficiency through thermally activated delayed fluorescence (TADF) emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional luminescent materials are used in organic electroluminescence devices, then the device structure can be kept simple, but the luminous efficiency and service life are insufficient

Engineering Contradiction:

Improveservice lifeVSAvoidmaterial structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs composite luminescent materials comprising a host material and a guest material with specific molecular structures (Formula 1 or Formula 1A). The host-guest system creates a composite material that achieves high luminous efficiency and long service life through energy transfer from host to guest, resolving the contradiction between simple structure and high performance.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes specific molecular parameters including the heteroatom types (X1-X6), aromatic ring structures (Ar1-Ar4), and substituent groups (R1-R8) in the luminescent compound formulas. By systematically varying these chemical parameters, the invention achieves enhanced stability and luminous efficiency without substantially increasing device structural complexity.

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If materials utilizing phosphorescence or delayed fluorescence are used, then luminous efficiency can be improved, but the device complexity and material synthesis difficulty increase

Engineering Contradiction:

Improveluminous efficiencyVSAvoidmaterial structure complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent utilizes thermally activated delayed fluorescence (TADF) by carefully designing molecular parameters including heteroatom composition (B, N, O, S), aromatic ring systems, and substituent patterns in Formulas 1 and 1A. This parameter optimization enables efficient triplet exciton utilization through TADF mechanism, achieving high luminous efficiency without requiring complex phosphorescent iridium complexes.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces traditional phosphorescence mechanisms (requiring heavy metal atoms like iridium) with organic TADF-based delayed fluorescence mechanisms. This substitution eliminates the need for expensive rare earth metals and complex synthesis procedures while maintaining high luminous efficiency through thermal activation of triplet excitons.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If advanced luminescent materials are developed to achieve high efficiency, then luminous efficiency improves, but manufacturing complexity and synthesis difficulty increase

Engineering Contradiction:

Improveluminous efficiencyVSAvoidmaterial synthesis ease

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent divides the luminescent material into two functional components: a host material (Formula 2) and a guest material (Formula 1 or 1A). This segmentation allows independent optimization of each component's synthesis and enables simplified manufacturing through sequential deposition or solution processing, reducing overall manufacturing complexity while achieving high luminous efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent optimizes synthesizability by selecting common heteroatoms (B, N, O, S) and standard aromatic building blocks (phenyl, naphthyl, pyridyl groups) in the molecular formulas. These parameter choices enable synthesis through well-established organic chemistry methods, improving ease of manufacture while maintaining high luminous efficiency through precise molecular design.

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 condensed cyclic compound in the emission layer significantly improves luminous efficiency, particularly in the blue light spectrum, with enhanced external quantum efficiency and prolonged device lifespan, outperforming comparative examples.

Implementation Method 1

incorporating heterocycles and benzoazaborine or dibenzoazaborine rings to enhance luminous efficiency through thermally activated delayed fluorescence (TADF) emission

Methodology Applied

Scientific EffectThermally activated delayed fluorescence (TADF): Luminescence

Data Source

PatentUS11839150B2Organic electroluminescence device and condensed cyclic compound for organic electroluminescence device

Publication Date: 2023.12.05 SAMSUNG DISPLAY CO LTD

AI summary

An organic electroluminescence device includes a first electrode, a second electrode, and an emission layer disposed between the first electrode and the second electrode, wherein the emission layer includes a condensed cyclic compound represented by Formula 1, and the organic electroluminescence device exhibits high efficiency characteristics.