MADF OLED Emitters Using Pt/Pd Complexes for Stable Light Emission

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Solution Overview

Problem

There is a need for efficient and stable organic light emitting diode (OLED) components that can efficiently emit light with improved performance and longevity, as existing OLEDs face challenges in achieving high internal efficiency and stability.

Innovation Solution

The development of specific organic compounds, such as those represented by General Formula I, which include Pt(II) or Pd(II) complexes with various substituents, are used in OLEDs to enhance light emission efficiency through increased conjugation, leading to improved MADF efficiency and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If phosphorescent OLEDs using Iridium, palladium or platinum complexes are used to achieve high internal efficiency, then light emission efficiency is improved, but device complexity and material cost increase

Engineering Contradiction:

Improvelight emission efficiencyVSAvoidmaterial complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces expensive, rare metal complexes (Iridium, Palladium, Platinum) with organic compounds containing common metals like Copper(I) or organic emitters. These organic materials are more abundant, cheaper, and can be processed more easily while achieving comparable or superior efficiency through delayed fluorescence mechanisms.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the emission mechanism from phosphorescence (requiring heavy metals with strong spin-orbit coupling) to delayed fluorescence (using organic compounds with appropriate HOMO-LUMO gaps and excited state dynamics). This parameter change in the emission pathway allows using simpler, less expensive materials while maintaining high internal quantum efficiency.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If conventional OLED materials are used, then fabrication is simpler, but performance and stability are insufficient

Engineering Contradiction:

Improvefabrication simplicityVSAvoiddevice stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent employs composite material systems where Copper(I) complexes are combined with specific organic ligands (such as N-heterocyclic carbenes, phosphines, or cyclometalating ligands) to create hybrid emissive layers. These composite materials leverage the advantages of both metal coordination chemistry and organic semiconductor properties, achieving high stability and efficiency while remaining compatible with existing OLED fabrication processes.

Inventive Principle:

Principle #40Composite materials

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 these compounds in OLEDs results in enhanced light emission efficiency and stability, addressing the need for improved performance and longevity in organic light emitting diodes.

Implementation Method 1

as these metal complexes have strong Spin-Orbital Coupling, they can efficiently emit light from their triplet exited state and reach nearly 100% internal efficiency

Methodology Applied

Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 2

Methodology Applied

Scientific EffectMetal assisted delayed fluorescence:

Data Source

PatentUS11945985B2Metal assisted delayed fluorescent emitters for organic light-emitting diodes

Publication Date: 2024.04.02 THE ARIZONA BOARD OF REGENTS ON BEHALF OF THE UNIV OF ARIZONA

AI summary

Compounds of General Formula I may harvest electrogenerated excitons via metal-assisted delayed fluorescence (MADF). The compounds have utility in light emitting diodes and light emitting devices.