Aromatic Amine Derivative for OLED Hole Transport
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Solution Overview
Problem
Existing organic electroluminescent devices face challenges with low glass transition temperature and poor film-forming properties of hole transport materials, leading to short device lifetime and inefficient luminous performance.
Innovation Solution
Development of an aromatic amine derivative with a linearly extending π-conjugation system connected to a non-planar, high molecular weight arylamino group, incorporating heterocyclic aromatic rings for improved thermal stability and redox repeatability, used in the hole transporting layer of OLED devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If triarylamine is used as hole transport material, then carrier mobility is improved, but glass transition temperature is low and film-forming properties are poor
Solution Approach 1:
The patent combines triarylamine units with rigid heterocyclic aromatic rings (such as triphenylene, coronene, or circumtrioxane) to create composite molecular structures. This composite approach allows the material to simultaneously exhibit high carrier mobility from the triarylamine component and improved thermal stability and film-forming properties from the rigid heterocyclic core, directly resolving the technical contradiction between carrier mobility and glass transition temperature.
2Speed
If pentacene compounds are used as hole transport material, then carrier mobility is improved, but HOMO level is high and redox repeatability is poor, resulting in short device lifetime
Solution Approach 1:
The patent modifies the HOMO level parameter by incorporating electron-withdrawing heterocyclic aromatic rings into the molecular structure. This parameter change lowers the HOMO level compared to pentacene, improving redox repeatability and device lifetime while maintaining high carrier mobility through the extended π-conjugation system and planar molecular structure.
3Productivity
If conventional hole transport materials are used, then device can operate, but luminous efficiency is low and device lifetime is short
Solution Approach 1:
The patent introduces local heterocyclic aromatic ring structures (such as triphenylene, coronene, or circumtrioxane units) within the hole transport material molecule. These local structural modifications create regions of enhanced electron delocalization and improved charge transport pathways, which locally enhance luminous efficiency while the overall molecular stability from the rigid core structure extends device lifetime.
Data Source
AI summary
The present invention relates to the field of organic electroluminescent technology, particularly relates to an aromatic amine derivative, its preparation method, uses and organic electroluminescent devices. The technical aim of the present invention is to improve the film forming ability and the redox repeatability. The aromatic amine derivative has the structure of formula I, wherein, R1, R2, R3 and R4 each independently represent a hydrogen, a substituted or unsubstituted C1-C40 alkyl, a substituted or unsubstituted C1-C40 alkoxy, a substituted or unsubstituted C3-C40 cycloalkyl, a substituted or unsubstituted C6-C50 aryl group, a substituted or unsubstituted C3-C50 heteroaryl containing one or two heteroatoms selected from N, O and S, or a substituted or unsubstituted C10-C40 fused aryl group formed together with the phenyl group linked therewith; wherein, m, n, p and q each independently represent 0, 1, 2, 3, 4 or 5; the substituents are one or more groups selected from the group consisting of a halogen, a C1-C10 alkyl, a C1-C10 alkoxy, a C3-C20 cycloalkyl, a C6-C20 aryl group or a C4-C20 heteroaryl group. The present invention may be applied in organic electroluminescent devices.