Metal Complex Red Phosphorescent Emitters for OLED Efficiency

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Solution Overview

Problem

Current organic light-emitting diodes (OLEDs) face challenges in achieving high external quantum efficiency, good color, and long lifetime for red phosphorescent materials, particularly in terms of external quantum efficiency and color stability.

Innovation Solution

A compound with the structure M(LA)x(LB)y(LC)z is developed, where M is a metal with an atomic number greater than 40, and ligands LA, LB, and LC are specifically designed to form a metal complex that serves as a red phosphorescent material, enhancing external quantum efficiency and color performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional red phosphorescent materials are used in OLEDs, then the device can emit red light, but the external quantum efficiency and color stability are insufficient

Engineering Contradiction:

Improveexternal quantum efficiencyVSAvoidcolor stability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent modifies the chemical structure of phosphorescent materials by changing ligand parameters (using specific bipyridine and phenanthroline derivatives with particular substituents) to optimize the metal complex properties, thereby improving external quantum efficiency while maintaining color stability in red phosphorescent OLEDs

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite phosphorescent materials consisting of metal centers (Ir, Pt, Os) coordinated with specifically designed organic ligands (bipyridine and phenanthroline derivatives), creating composite structures that achieve both high external quantum efficiency and stable color emission

Inventive Principle:

Principle #40Composite materials

2Duration of action of stationary object

If conventional phosphorescent materials are used, then the OLED can operate, but the operational lifetime is limited

Engineering Contradiction:

Improveoperational lifetimeVSAvoidperformance consistency

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent optimizes molecular parameters of phosphorescent emitters by selecting specific metal centers (Ir, Pt, Os) and ligand structures (with particular substituents like alkyl, aryl, heteroaryl groups) to enhance operational lifetime while maintaining consistent performance characteristics in red phosphorescent OLEDs

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 compound improves the external quantum efficiency and color stability of red phosphorescent OLEDs, leading to longer operational lifetimes and better performance compared to existing materials.

Implementation Method 1

Methodology Applied

Scientific EffectPhosphorescence: Phosphorescence

Data Source

PatentUS11919916B2Organic electroluminescent materials and devices

Publication Date: 2024.03.05 UNIVERSAL DISPLAY CORP

AI summary

A compound that has the structure according to Formula M(LA)x(LB)y(LC)z is disclosed. In Formula M(LA)x(LB)y(LC)z, ligand LA isligand LB isand ligand LC isand OLEDs and formulations containing these compounds are disclosed. In Formula M(LA)x(LB)y(LC)z; M is a metal; x is 1 or 2; X1-X4 and A1-A8 are C or N; at least one of A1-A8 is N; X is O, S, or Se; two adjacent RB form a six-member aromatic ring E fused to ring B; and each RA-RE and R1R4 is independently hydrogen or a substituent.