Organometallic Compound for OLED Driving Voltage Reduction

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Solution Overview

Problem

Organic light-emitting devices (OLEDs) face challenges in achieving low driving voltage, high efficiency, and long lifespan while maintaining high brightness and efficiency.

Innovation Solution

An organometallic compound represented by Formula 1, which includes a transition metal, specific ligands, and cycloalkene structures, is used in the organic layer of OLEDs to enhance hole current, reduce nonradiative transitions, and increase LUMO energy levels, thereby lowering driving voltage and improving device efficiency and lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional organic light-emitting devices are used, then device structure is simple, but driving voltage is high and efficiency is low

Engineering Contradiction:

Improvedriving voltageVSAvoiddevice structure

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The patent introduces a novel organometallic compound with specific molecular structure parameters (Formula 1 with transition metal M, ligands L1-L3, and cycloalkene structures) that changes the energy level parameters (HOMO and LUMO) and charge transport parameters of the emission layer, thereby reducing driving voltage and improving efficiency without fundamental structural changes to the OLED device

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional emission layers are used, then device manufacturing is easy, but lifespan is short and efficiency is low

Engineering Contradiction:

Improvedevice lifespanVSAvoidmanufacturing process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a composite organometallic compound structure combining transition metal center with organic ligands (L1, L2, L3) containing cycloalkene moieties, creating a material that simultaneously achieves high efficiency, long lifespan, and ease of manufacture through molecular-level composite design rather than complex device-level structures

Inventive Principle:

Principle #40Composite materials

3Productivity

If conventional organometallic compounds are used, then device structure is simple, but molecule-molecule stackings occur causing reduced efficiency

Engineering Contradiction:

Improvedevice efficiencyVSAvoidmolecular structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies local quality by introducing cycloalkene structures at specific positions within the ligand molecules (L1-L3) of the organometallic compound, creating localized steric hindrance that prevents unwanted molecule-molecule stackings in the emission layer, thereby maintaining high device efficiency without requiring overall structural complexity

Inventive Principle:

Principle #3Local quality

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 organometallic compound in the OLEDs results in devices with low driving voltage, high efficiency, and extended lifespan by increasing HOMO energy levels and blocking electrons, while reducing molecule-molecule stackings and nonradiative transitions.

Implementation Method 1

increasing HOMO energy levels and blocking electrons

Methodology Applied

Scientific EffectHOMO energy level adjustment:

Implementation Method 2

blocking electrons

Methodology Applied

Scientific EffectElectron blocking:

Implementation Method 3

reducing nonradiative transitions

Methodology Applied

Scientific EffectNonradiative transition reduction:

Implementation Method 4

increase LUMO energy levels

Methodology Applied

Scientific EffectLUMO energy level adjustment:

Data Source

PatentUS9735376B2Organometallic compound and organic light-emitting device including the same

Publication Date: 2017.08.15 SAMSUNG ELECTRONICS CO LTD

AI summary

An organometallic compound represented by Formula 1:M(L1)n1(L2)n2(L3)n3 Formula 1wherein in Formula 1, M, L1, L2, L3, n1, n2, and n3 are the same as defined in the specification.