Adamantyl Diamine OLED Material for Hole Transport and Stability
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Solution Overview
Problem
Current organic electroluminescent devices face challenges in achieving high efficiency and long service life due to the low hole transport rate of monoamine structures, which also lead to crystallization issues at high temperatures, reducing device performance.
Innovation Solution
A diamine structure with adamantyl substitution is introduced, which enhances hole mobility and glass transition temperature, thereby improving hole transport efficiency and inhibiting crystallization, and is used as a hole transport or electron-blocking layer in organic electroluminescent devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a monoamine structure is used as hole transport material, then the device structure is simple, but the hole transport rate is low resulting in reduced efficiency and service life
Solution Approach 1:
The patent introduces a diamine structure as a composite molecular design that combines two amine groups within a single molecule. This composite structure enables simultaneous achievement of high hole transport rate and long service life, resolving the contradiction between structural simplicity and transport performance
2Productivity
If NPD is used as hole transport material, then excellent hole transport performance is achieved, but the glass transition temperature is only 96°C causing crystallization at high temperature
Solution Approach 1:
The patent modifies the molecular parameters by introducing a diamine structure with specific substituents (R1-R6 groups) that increase the glass transition temperature to above 100°C while maintaining excellent hole transport performance. This parameter change prevents crystallization at high temperature while preserving transport efficiency
3Productivity
If the hole transport rate is increased to improve efficiency, then light emitting efficiency improves, but the service life is reduced due to crystallization
Solution Approach 1:
The diamine structure acts as a composite molecular design that simultaneously achieves high hole transport rate (improving efficiency) and high glass transition temperature above 100°C (preventing crystallization). This composite approach resolves the contradiction between efficiency and service life by providing both high productivity and long duration of action
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 diamine structure with adamantyl substitution results in organic electroluminescent devices with lower drive voltage, higher light emitting efficiency, and longer service life by balancing hole and electron transport efficiencies and preventing crystallization.
Implementation Method 1
the diamine structure has a high HOMO energy level and hole mobility, and may show a higher efficiency and a longer service life than a device made of a monoamine material
Implementation Method 2
The diamine structure with adamantyl substitution enhances hole mobility and glass transition temperature, thereby improving hole transport efficiency and inhibiting crystallization
Data Source
AI summary
The present invention relates to an organic electroluminescent material and organic electroluminescent device thereof. The organic electroluminescent material has the structural formula as shown in formula 1. Compared with a monoamine structure containing an adamantyl group, the diamine structure disclosed in the present invention has higher HOMO energy level and hole mobility, and can exhibit higher efficiency and service life than a monoamine material device. The organic electroluminescent device comprising the organic electroluminescent material has lower driving voltage, and higher luminous efficiency and service life.