Delayed Fluorescent Compound Triazine Spiroindeno Structure

Solution Overview

Problem

Conventional fluorescent materials used in organic light emitting diodes (OLEDs) have low emitting efficiency due to the involvement of only singlet excitons in light emission, limiting their quantum efficiency.

Innovation Solution

A delayed fluorescent compound with a triazine moiety and a spiroindeno(thio)xanthen moiety is introduced, allowing both triplet and singlet excitons to participate in emission, enhancing efficiency through charge transfer and intersystem transition mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional fluorescent materials are used in OLEDs, then the device structure is simple and ease of manufacture is maintained, but the emitting efficiency and quantum efficiency are low due to involvement of only singlet excitons

Engineering Contradiction:

Improveease of manufactureVSAvoidemitting efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent employs composite material design by combining the delayed fluorescent compound (containing triazine and spiroindeno(thio)xanthen moieties) with a host material in the emitting layer. This composite approach enables both triplet and singlet excitons to contribute to light emission, achieving theoretical quantum efficiency of 100% while maintaining manufacturability through conventional OLED fabrication processes

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention changes the chemical and photophysical parameters of the emitting material by introducing a delayed fluorescent compound with specific molecular structure (Formula 1) and composition ratios (5-50 wt%). This parameter change enables exploitation of both singlet and triplet excitons, transforming the emitting mechanism from conventional fluorescence to delayed fluorescence with enhanced quantum efficiency

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If conventional fluorescent materials are used in OLEDs, then the material selection and device structure are simple, but the quantum efficiency is limited due to involvement of only singlet excitons in light emission

Engineering Contradiction:

Improvedevice complexityVSAvoidquantum efficiency

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent converts the previously harmful or wasted triplet excitons (which normally do not emit light in conventional fluorescent materials) into useful light-emitting species through the delayed fluorescence mechanism. The triplet excitons are harvested via reverse intersystem crossing and contribute to light emission, turning what was previously a loss into a beneficial contribution to quantum efficiency

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The delayed fluorescent compound acts as an intermediary between the host material and the final light emission. It facilitates the conversion of triplet excitons from the host into singlet excitons that can emit light, mediating the energy transfer and exciton transformation processes to achieve high quantum efficiency while maintaining a relatively simple device structure

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 delayed fluorescent compound achieves high emitting efficiency, with theoretical quantum efficiency of 100%, improving the performance of OLEDs by engaging both triplet and singlet excitons in light emission.

Implementation Method 1

A delayed fluorescent compound with a triazine moiety and a spiroindeno(thio)xanthen moiety is introduced, allowing both triplet and singlet excitons to participate in emission, enhancing efficiency through charge transfer and intersystem transition mechanisms.

Methodology Applied

Scientific EffectIntersystem transition:

Implementation Method 2

A delayed fluorescent compound with a triazine moiety and a spiroindeno(thio)xanthen moiety is introduced, allowing both triplet and singlet excitons to participate in emission, enhancing efficiency through charge transfer and intersystem transition mechanisms.

Methodology Applied

Scientific EffectCharge transfer:

Implementation Method 3

The delayed fluorescent compound achieves high emitting efficiency, with theoretical quantum efficiency of 100%, improving the performance of OLEDs by engaging both triplet and singlet excitons in light emission.

Methodology Applied

Scientific EffectDelayed fluorescence:

Data Source

PatentUS11667647B2Delayed fluorescent compound, and organic light emitting diode and organic light emitting display device including the same

Publication Date: 2023.06.06 LG DISPLAY CO LTD

AI summary

The disclosure provides a delayed fluorescent compound of the Formulaand an organic light emitting diode including a first electrode, a second electrode and an organic emitting layer between the first and second electrodes, where the delayed fluorescent compound is included in the organic emitting layer, and an organic light emitting display device including the organic emitting layer.