OLED Emitting Layer Materials for Low Voltage and Longer Lifetime

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Solution Overview

Problem

Current organic light emitting devices face challenges in achieving low driving voltage and long lifetime due to limitations in material performance and efficiency.

Innovation Solution

Incorporating a compound of Chemical Formula 1 and a compound of Chemical Formula 2 in the light emitting layer, which includes specific aryl and heterocyclic groups, enhances electron mobility and facilitates hole injection, resulting in improved device efficiency and longevity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional organic materials are used in the light emitting layer, then the device structure is simple, but the driving voltage is high and lifetime is short

Engineering Contradiction:
Improvedevice lifetimeVSAvoiddriving voltage
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent uses a composite material system consisting of compound 1 (host material with dibenzofuran group) and compound 2 (guest material with specific aromatic rings) in the light emitting layer. This composite approach enables simultaneous achievement of low driving voltage (due to improved electron mobility from compound 1) and long lifetime (due to efficient energy transfer and high color purity from compound 2), resolving the technical contradiction between reliability and energy consumption.

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional organic materials are used in the light emitting layer, then the material selection is simple, but the electron mobility is low and hole injection is poor

Engineering Contradiction:
Improvedevice efficiencyVSAvoidmaterial structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by designing compound 1 with a dibenzofuran group specifically positioned to enhance electron mobility in the host material, while compound 2 is designed with specific aromatic rings (Cy1-Cy3) and substituents (Ra, Rb) to optimize hole injection and energy transfer. This localized functional design in each molecule enables high device efficiency without requiring complex multi-component systems.

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 use of these compounds in the light emitting layer reduces driving voltage and increases the lifetime of the organic light emitting device while maintaining high color purity and efficiency.

Implementation Method 1

the compound of Chemical Formula 1 of the present disclosure increases electron mobility by introducing a dibenzofuran group, an electron withdrawing group, to an anthracene structure that has been used in the art, and as a result, polarity of molecules increases facilitating electron injection

Methodology Applied
Scientific EffectElectron mobility enhancement through molecular structure design:

Implementation Method 2

by substituting a No. 2 position of the anthracene with an aryl group or a heterocyclic group, hole injection is facilitated by increasing a HOMO level of the molecule

Methodology Applied
Scientific EffectHole injection through HOMO level adjustment:

Implementation Method 3

materials having, when excitons produced by holes and electrons recombining in a light emitting layer are formed, high light emission efficiency converting the excitons to light are preferred

Methodology Applied
Scientific EffectLight emission from exciton recombination: Electroluminescence

Data Source

PatentUS11980093B2Organic light emitting diode
Publication Date: 2024.05.07 LG CHEM LTD

AI summary

An organic light emitting device including a compound of Chemical Formula 1 and a compound of Chemical Formula 2, wherein