Light-Emitting Device Interlayer to Suppress Dexter Transfer

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Solution Overview

Problem

Existing light-emitting devices face challenges in improving luminescence efficiency, lifespan, and color purity due to Dexter energy transfer between heterogeneous molecules.

Innovation Solution

Incorporating a specific interlayer in the light-emitting device comprising compounds represented by Formulas 1 and 2, which satisfy Condition 1, to suppress Dexter energy transfer and enhance structural stability, thereby preventing or reducing π-π stacking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional emission layers are used in light-emitting devices, then device operation is maintained, but luminescence efficiency is limited due to Dexter energy transfer between heterogeneous molecules

Engineering Contradiction:

Improveluminescence efficiencyVSAvoidenergy loss through Dexter transfer

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent introduces a host-guest system where the host compound acts as an intermediary medium. The host (compound of Formula 1) with specific structural features (Y1, Y2, Y3 groups and L1-L3 linkers) mediates energy transfer to the guest compound (Formula 2), enabling efficient luminescence while preventing direct Dexter energy transfer between heterogeneous molecules through controlled host-guest interactions.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies molecular parameters by designing compounds with specific structural characteristics - Y1, Y2, Y3 may be selected from O, S, Se, C(R)(R'), Si(R)(R'), or N(R), with adjustable linker groups L1-L3 and substituents R1-R7. These parameter changes optimize the host-guest energy transfer while suppressing detrimental Dexter transfer between heterogeneous molecules.

Inventive Principle:

Principle #35Parameter changes

2Illumination intensity

If emission layers with high molecular density are used, then luminance is improved, but lifespan is reduced due to increased Dexter energy transfer and molecular degradation

Engineering Contradiction:

ImproveluminanceVSAvoiddevice lifespan

Core Design Contradiction:

Illumination intensityVSDuration of action of stationary object

Solution Approach 1:

The host compound serves as a protective intermediary that separates guest molecules, reducing direct heterogeneous molecular contacts. This mediation maintains high luminance through efficient energy transfer while extending device lifespan by minimizing degradation pathways associated with direct Dexter energy transfer between different molecular species.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The emission layer employs a composite host-guest material system where compound (1) and compound (2) are combined in specific ratios. This composite structure achieves high luminance through synergistic effects while improving stability and lifespan by distributing stress and reducing molecular degradation through the protective host matrix.

Inventive Principle:

Principle #40Composite materials

3Illumination intensity

If emission layers with broad spectral emission are used, then luminance coverage is improved, but color purity is reduced due to Dexter energy transfer between heterogeneous molecules

Engineering Contradiction:

Improveluminance coverageVSAvoidcolor purity

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The host-guest system acts as a spectral intermediary where the host absorbs energy and transfers it to the guest, which then emits light with narrow, pure spectral bands. This mediation maintains broad luminance coverage through host absorption while achieving high color purity in emission through the guest's characteristic narrow bandwidth, preventing spectral broadening from heterogeneous Dexter transfer.

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 solution results in improved luminescence efficiency, extended lifespan, and enhanced color purity of the light-emitting device by minimizing Dexter energy transfer and π-π stacking.

Implementation Method 1

suppressing or reducing Dexter energy transfer between heterogeneous molecules

Methodology Applied

Scientific EffectDexter energy transfer:

Implementation Method 2

preventing or reducing π-π stacking

Methodology Applied

Scientific Effectπ-π stacking:

Data Source

PatentUS20250248306A1Light-emitting device and electronic apparatus and electronic equipment including the same

Publication Date: 2025.07.31 SAMSUNG DISPLAY CO LTD

AI summary

A light-emitting device including a first electrode, a second electrode opposite to (e.g., facing) the first electrode, and an interlayer arranged between the first electrode and the second electrode is provided. The interlayer includes an emission layer having at least a first compound and a second compound. The first compound includes a pentacyclic core with a nearly planar geometry and a hexacyclic peripheral section that is twisted to shield the pentacyclic core and prevent or reduce intermolecular π-π stacking. The core of the second compound may be a triazine group having bulky substituents that prevent or reduce intermolecular π-π stacking with the first compound.