Organic Electroluminescent Composition for Energy Transfer Control

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Solution Overview

Problem

Existing organic electroluminescent elements face challenges in achieving high luminous efficiency and long lifetime due to energy transfer issues between phosphorescent metal complexes and fluorescent compounds, leading to thermal deactivation and reduced luminance, particularly under high current densities.

Innovation Solution

Incorporating a specific phosphorescent metal complex with a core-shell structure and a fluorescent compound, where the complex satisfies certain molecular volume and energy level conditions, to suppress Dexter-type energy transfer and enhance Förster-type energy transfer, thereby increasing luminous efficiency and lifetime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a phosphorescent metal complex and a fluorescent compound coexist to emit light, then luminous efficiency can be improved, but thermal deactivation occurs from T1 of the phosphorescent compound to T1 of the fluorescent compound, reducing lifetime

Engineering Contradiction:

Improveluminous efficiencyVSAvoidlifetime

Core Design Contradiction:

Use of energy by moving objectVSDuration of action of stationary object

Solution Approach 1:

The patent introduces a host compound as an intermediary material that facilitates energy transfer from the phosphorescent metal complex to the fluorescent compound. The host compound acts as a mediator that enables efficient energy transfer while preventing direct harmful interactions between the phosphorescent and fluorescent compounds, thus improving luminous efficiency without sacrificing lifetime

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the energy level parameters of the fluorescent compound by selecting compounds with specific triplet energy levels (T1) that are higher than those of the phosphorescent metal complex. This parameter change prevents reverse energy transfer and thermal deactivation, allowing the system to maintain both high luminous efficiency and long lifetime

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If a phosphorescent metal complex is used as a fluorescent sensitizer to cause fluorescence emission, then luminous efficiency can be improved, but Dexter type energy transfer from T1 of the phosphorescent metal complex to T1 of the fluorescent compound occurs, causing thermal deactivation

Engineering Contradiction:

Improveluminous efficiencyVSAvoidthermal deactivation

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent converts the potentially harmful Dexter type energy transfer into a beneficial process by carefully designing the energy level hierarchy. By ensuring the fluorescent compound has higher T1 energy than the phosphorescent metal complex, the system enables efficient energy transfer to the fluorescent compound's S1 state for fluorescence emission, while preventing transfer to the fluorescent compound's T1 state that would cause thermal deactivation

Inventive Principle:

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

Solution Approach 2:

The patent changes the energy level parameters of the fluorescent compound selection, specifically choosing compounds with T1 energy levels higher than the phosphorescent metal complex. This parameter change transforms the energy transfer pathway, enabling beneficial fluorescence emission while blocking harmful thermal deactivation pathways

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 solution enables high-efficiency phosphorescence and fluorescence emissions with extended lifetime by minimizing thermal deactivation and quenching, even under high current densities, reducing the need for costly high-gas-barrier layers.

Implementation Method 1

an element that emits light using light emission (fluorescence and phosphorescence) when this exciton is deactivated

Methodology Applied

Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 2

an element that emits light using light emission (fluorescence and phosphorescence) when this exciton is deactivated

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Implementation Method 3

Electrons and holes are injected into the light emitting layer, and an exciton is generated by recombining them

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 4

metal complexes having heavy atoms such as Ir and Pt are capable of spin inversion by the heavy atom effect, which is inherently forbidden from the singlet excited state to the triplet excited state

Methodology Applied

Scientific EffectHeavy atom effect:

Data Source

PatentUS20260114114A1Organic electroluminescent element and composition for organic materials

Publication Date: 2026.04.23 UDC IRELAND

AI summary

The present invention addresses the problem of providing: an organic electroluminescent element which is capable of emitting light with high luminous efficiency, while having a long service life; and a composition for organic materials. An organic electroluminescent element according to the present invention comprises a positive electrode, a negative electrode and one or more organic functional layers arranged between the positive electrode and the negative electrode, and is characterized in that: the organic functional layers contain a phosphorescent metal complex and a fluorescent compound; the phosphorescent metal complex is a compound having a structure that is represented by a specific general formula; and the phosphorescent metal complex is a core-shell type dopant that satisfies a specific formula.