Iridium OLED Emitters With Azadibenzofuran for Saturated Green

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Solution Overview

Problem

Existing OLED materials struggle to achieve saturated green color emission, as previous modifications to extend conjugation and lower LUMO levels result in red-shifted emission, making them less suitable for display applications.

Innovation Solution

The introduction of azadibenzofuran substitution in iridium complexes with 2-phenylpyridine and 2-(4-dibenzofuran)-pyridine ligands, which unexpectedly leads to blue-shifted emission spectra, making them more suitable for saturated green color displays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conjugation is extended and LUMO level is lowered to improve emission wavelength tuning, then emission wavelength can be adjusted, but the emission shifts to red, resulting in loss of saturated green color

Engineering Contradiction:

Improveemission wavelength tuningVSAvoidsaturated green color saturation

Core Design Contradiction:

Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by modifying the molecular structure of iridium complexes through introducing azadibenzofuran substitution at specific positions (A1-A4 or A5-A8) in the ligand framework. This structural parameter change results in blue-shifted emission spectra, counteracting the typical red-shift caused by extended conjugation, thereby maintaining saturated green color while enabling wavelength tuning.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials by combining azadibenzofuran units with phenylpyridine ligands in iridium complexes. This composite molecular structure integrates the beneficial properties of both components: the azadibenzofuran provides blue-shifting effect and the phenylpyridine maintains the phosphorescent emission characteristics, achieving both wavelength control and color saturation.

Inventive Principle:

Principle #40Composite materials

2Temperature

If conventional OLED materials are used to achieve red-shifted emission, then emission wavelength can be extended, but saturated green color cannot be achieved

Engineering Contradiction:

Improveemission wavelength extensionVSAvoidsaturated green color achievement

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The patent applies the inversion principle by reversing the typical trend in emission wavelength shifting. Instead of allowing conjugation extension to cause red-shift, the azadibenzofuran substitution introduces a blue-shifting effect that inverts the expected behavior, enabling green color emission while maintaining extended conjugation for wavelength tuning capability.

Inventive Principle:

Principle #13The other way round (Inversion)

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 compounds with azadibenzofuran substitution exhibit blue-shifted emission spectra, enhancing their suitability for achieving saturated green colors in display applications.

Implementation Method 1

OLEDs make use of thin organic films that emit light when voltage is applied across the device

Methodology Applied

Scientific EffectPhosphorescence: Phosphorescence

Data Source

PatentUS20250359473A1Organic electroluminescent materials and devices

Publication Date: 2025.11.20 UNIVERSAL DISPLAY CORP

AI summary

Novel iridium complexes containing phenylpyridine and pyridyl aza-benzo fused ligands are described. The complexes are useful as light emitters when incorporated into OLEDs.