Dibenzofuran Host Compounds for OLED Efficiency and Lifetime

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Solution Overview

Problem

Current organic electroluminescent devices, particularly phosphorescent OLEDs, face challenges with non-saturated blue color, short device lifetime, high operating voltage, and efficiency roll-off at high brightness, limiting their commercialization and performance.

Innovation Solution

Development of new compounds with a specific structure (Formula 1) for use as host materials or electron transport materials in organic electroluminescent devices, which improve device performance and extend lifetime by optimizing the singlet-triplet gap for enhanced efficiency and emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If phosphorescent emitters are used in OLEDs, then internal quantum efficiency is improved (achieving 100% IQE), but device lifetime is shortened and operating voltage increases

Engineering Contradiction:

Improveinternal quantum efficiencyVSAvoiddevice lifetime

Core Design Contradiction:

Use of energy by moving objectVSDuration of action of stationary object

Solution Approach 1:

The patent modifies molecular parameters by introducing specific substituent groups (R1-R6) at defined positions on the dibenzofuran core structure, and by selecting specific heteroatoms (O, S, or Se) at the X position. These parameter changes in the molecular structure optimize the singlet-triplet gap and improve device lifetime while maintaining high efficiency

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If phosphorescent emitters are used in OLEDs, then internal quantum efficiency is improved, but operating voltage becomes high

Engineering Contradiction:

Improveinternal quantum efficiencyVSAvoidoperating voltage

Core Design Contradiction:

Use of energy by moving objectVSPower

Solution Approach 1:

The patent optimizes molecular parameters by selecting specific heteroatoms (O, S, or Se) and introducing electron-donating or electron-withdrawing substituent groups at strategic positions. These parameter changes tune the HOMO-LUMO energy levels and improve charge transport, thereby reducing operating voltage while maintaining high internal quantum efficiency

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If conventional OLED structures are used, then fabrication is simplified, but device lifetime is short

Engineering Contradiction:

Improvefabrication simplicityVSAvoiddevice lifetime

Core Design Contradiction:

Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The patent changes the chemical parameter of the host material by using dibenzofuran-based compounds with specific substituent patterns. These parameter changes improve material stability and reduce degradation pathways, extending device lifetime while maintaining compatibility with conventional vacuum thermal evaporation fabrication processes

Inventive Principle:

Principle #35Parameter changes

4Use of energy by moving object

If blue phosphorescent devices are used, then high efficiency is achieved, but color saturation is poor and device lifetime is short

Engineering Contradiction:

ImproveefficiencyVSAvoidcolor saturation

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent optimizes the molecular parameters of the host material by introducing specific electron-donating or electron-withdrawing groups at defined positions on the dibenzofuran core. These parameter changes enable better energy level matching with the phosphorescent emitter, improving color saturation through enhanced exciton confinement while maintaining high efficiency and extended lifetime

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 new compounds enhance the internal quantum efficiency, achieve more saturated colors, and prolong the device lifetime, addressing the limitations of existing OLEDs by improving the overall performance and efficiency of organic electroluminescent devices.

Implementation Method 1

Once a bias is applied to the device, green light was emitted from the device

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

Forrest and Thompson reported phosphorescent OLED, which uses triplet emission from heavy metal containing complexes as the emitter

Methodology Applied

Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 3

Adachi achieved high efficiency through thermally activated delayed fluorescence (TADF) of organic compounds. These emitters have small singlet-triplet gap that makes the transition from triplet back to singlet possible

Methodology Applied

Scientific EffectThermally activated delayed fluorescence:

Data Source

PatentUS20240032417A1Organic electroluminescent material and device thereof

Publication Date: 2024.01.25 BEIJING SUMMER SPROUT TECH CO LTD

AI summary

Provided are an organic electroluminescent material and a device comprising the same. The organic electroluminescent material is a compound having a structure of Formula 1. These new compounds can be applied in organic electroluminescent devices, for example, as host materials, transport materials (e.g., electron transport materials), etc., in organic electroluminescent devices, and can provide better device performance and especially improve the device lifetime. Further provided are an organic electroluminescent device including the compound and a compound composition including the compound.