Condensed Cyclic Compound for OLED TADF Efficiency

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current organic light-emitting devices (OLEDs) face limitations in achieving high luminescence efficiency and low driving voltage due to challenges in exciton formation and recombination rates, particularly in controlling the energy difference between singlet and triplet states.

Innovation Solution

Incorporation of a condensed cyclic compound represented by Formula 1, which separates into electron donor and acceptor moieties, facilitating charge transfer and preventing orbital overlap, thereby enabling thermal activated delayed fluorescence (TADF) and improving luminescence efficiency by allowing reverse intersystem crossing at room temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional OLED materials are used, then device structure is simple, but luminescence efficiency is low due to poor exciton formation and recombination

Engineering Contradiction:

Improveluminescence efficiencyVSAvoidmolecular structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The compound is divided into distinct electron donor and electron acceptor moieties that are spatially separated. This segmentation prevents orbital overlap while maintaining charge transfer capability, resolving the contradiction by enabling efficient exciton formation without requiring overly complex molecular structures.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses composite molecular structures combining electron donor and acceptor units within a single compound. This composite approach enables both charge transfer for efficient exciton formation and controlled energy levels for improved luminescence efficiency, addressing the contradiction between efficiency and structural simplicity.

Inventive Principle:

Principle #40Composite materials

2Productivity

If high luminescence efficiency is achieved through improved exciton formation, then driving voltage increases, but this contradicts the goal of low driving voltage operation

Engineering Contradiction:

Improveluminescence efficiencyVSAvoiddriving voltage

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The invention optimizes key parameters including the energy difference between singlet and triplet states (ΔEST), HOMO-LUMO energy levels, and charge transfer characteristics. By carefully tuning these parameters through molecular design, the compound achieves high luminescence efficiency while maintaining low driving voltage operation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The compound design incorporates proven electron donor and acceptor motifs that have demonstrated successful charge transfer behavior in similar systems. This approach allows optimization of luminescence efficiency without requiring excessive energy input, as the copied structural elements already exhibit favorable energy level alignments.

Inventive Principle:

Principle #26Copying

3Productivity

If electron donor and acceptor moieties are separated to prevent orbital overlap, then charge transfer is facilitated, but molecular design complexity increases

Engineering Contradiction:

Improvecharge transfer efficiencyVSAvoidmolecular design complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The molecule is segmented into distinct donor and acceptor blocks connected by linker groups. This segmentation achieves the necessary spatial separation for efficient charge transfer while using standardized structural motifs that simplify the overall design process, resolving the contradiction between charge transfer efficiency and design complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Linker groups serve as intermediaries connecting the electron donor and acceptor moieties. These linkers facilitate charge transfer while maintaining appropriate spatial separation, and their use of common chemical structures keeps the molecular design manageable despite the segmented architecture.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 enhances exciton formation rates, leading to OLEDs with low driving voltage, high efficiency, long lifespan, and high maximum quantum efficiency, while controlling energy states for improved luminescence.

Implementation Method 1

facilitating charge transfer and preventing orbital overlap, thereby enabling thermal activated delayed fluorescence (TADF) and improving luminescence efficiency by allowing reverse intersystem crossing at room temperature

Methodology Applied

Scientific EffectThermal activated delayed fluorescence (TADF): Fluorescence

Implementation Method 2

improving luminescence efficiency by allowing reverse intersystem crossing at room temperature

Methodology Applied

Scientific EffectReverse intersystem crossing: Fluorescence

Data Source

PatentUS11299502B2Condensed cyclic compound and organic light-emitting device including condensed cyclic compound

Publication Date: 2022.04.12 SAMSUNG DISPLAY CO LTD

AI summary

A condensed cyclic compound and an organic light-emitting device including the same are provided. When the condensed cyclic compound is used as an emission layer material in a device, the device may have excellent driving voltage, efficiency, and colorimetric purity. An organic light-emitting device including the condensed cyclic compound may have a low driving voltage, excellent efficiency, and a long lifespan.