Aromatic Amine Derivative Hole Transport Layer for Organic EL

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Solution Overview

Problem

Existing aromatic amine derivatives used in organic electroluminescent (EL) elements have insufficient light emission efficiency and lifetime, particularly due to a large energy barrier between the hole transporting layer and the light emitting layer, which hinders hole injection and reduces recombination efficiency.

Innovation Solution

An aromatic amine derivative with a specific structure, featuring an aromatic hydrocarbon group and a substituted or unsubstituted phenyl group, is used as a hole transporting material to reduce the energy barrier and enhance electron density, facilitating hole injection and recombination in the light emitting layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If aromatic amine derivatives with fluorene skeleton are used as hole transporting material, then operation voltage is reduced, but light emission efficiency decreases due to large energy barrier

Engineering Contradiction:

Improveoperation voltageVSAvoidlight emission efficiency

Core Design Contradiction:

Use of energy by stationary objectVSProductivity

Solution Approach 1:

The patent modifies the molecular structure of aromatic amine derivatives by introducing specific aromatic hydrocarbon groups (naphthyl, phenanthryl, or pyrenyl groups) at the para position of the phenyl ring. This structural parameter change optimizes the ionization potential and HOMO level of the hole transporting material, reducing the energy barrier between the hole transporting layer and light emitting layer while maintaining low operation voltage.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates composite hole transporting materials by combining aromatic amine derivatives with specific aromatic hydrocarbon groups. These composite structures integrate the benefits of low ionization potential (from the amine derivative) with optimized energy levels (from the aromatic hydrocarbon group), achieving both low operation voltage and high light emission efficiency.

Inventive Principle:

Principle #40Composite materials

2Device complexity

If conventional aromatic amine derivatives are used, then device structure is simple, but lifetime is insufficient

Engineering Contradiction:

Improvemolecular structure simplicityVSAvoidelement lifetime

Core Design Contradiction:

Device complexityVSDuration of action of stationary object

Solution Approach 1:

The patent introduces specific aromatic hydrocarbon groups (naphthyl, phenanthryl, or pyrenyl groups) at the para position of the phenyl ring in aromatic amine derivatives. This parameter change in molecular structure enhances the stability and charge transport capability of the hole transporting material, thereby extending the element lifetime while maintaining structural simplicity.

Inventive Principle:

Principle #35Parameter changes

3Use of energy by stationary object

If hole transporting layer material has small ionization potential, then low voltage operation is achieved, but energy barrier to light emitting layer increases

Engineering Contradiction:

Improveoperation voltageVSAvoidenergy barrier

Core Design Contradiction:

Use of energy by stationary objectVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the ionization potential parameter by introducing specific aromatic hydrocarbon groups at the para position of the phenyl ring. This parameter adjustment achieves a balanced energy level configuration where the hole transporting material has sufficiently low ionization potential for low voltage operation, while the HOMO level is optimized to minimize the energy barrier to the light emitting layer.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9184395B2Aromatic amine derivative and organic electroluminescent element using same

Publication Date: 2015.11.10 IDEMITSU KOSAN CO LTD

AI summary

To provide an organic EL element material that is capable of enhancing the light emission efficiency and the lifetime of the element as compared to an ordinary organic EL element material, and an organic EL element using the same. Specifically, to provide an aromatic amine derivative represented by Ar1Ar2Ar3N, and an organic EL element using the same. Representative compounds include the following.