Triarylamine Charge Transporting Material for Low Voltage OLEDs
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Solution Overview
Problem
Existing organic electroluminescent elements using phosphorescence emitting materials face issues with high driving voltage, low luminous efficiency, and durability, particularly when emitting green phosphorescence.
Innovation Solution
A charge transporting material with a triarylamine structure, containing an aryl or heteroaryl group at the para-position and a biphenyl skeleton with a p-phenylene group, is used to create a compound that reduces driving voltage and enhances luminous efficiency and durability in organic electroluminescent elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If previously reported charge transporting materials are used, then the organic electroluminescent element can emit green phosphorescence, but the driving voltage becomes too high
Solution Approach 1:
The patent modifies the molecular structure parameters of the charge transporting material by introducing specific substituent groups (aryl or heteroaryl groups) at the para-position of the triarylamine core structure. This structural parameter change optimizes the electronic properties, enabling low driving voltage operation while maintaining green phosphorescence emission performance.
Solution Approach 2:
The patent creates a composite molecular structure by combining triarylamine core with biphenyl skeleton and additional aryl/heteroaryl substituents. This composite structure integrates the advantages of different molecular components to achieve both low driving voltage and high reliability for green phosphorescence emission.
2Use of energy by stationary object
If previously reported charge transporting materials are used, then the element can operate, but the luminous efficiency becomes low
Solution Approach 1:
The patent optimizes the molecular parameters of the charge transporting material by adjusting the substituent groups and core structure, which improves the charge transport properties and exciton management. This leads to enhanced luminous efficiency and reduced energy loss in the organic electroluminescent element.
3Duration of action of stationary object
If previously reported charge transporting materials are used, then the element can function, but the durability is reduced
Solution Approach 1:
The patent modifies the chemical structure parameters of the charge transporting material to improve molecular stability and resistance to degradation. The optimized structure with specific substituent groups enhances the durability and operational stability of the organic electroluminescent element.
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 proposed charge transporting material allows for organic electroluminescent elements to be driven at low voltage with improved luminous efficiency and durability, specifically for green phosphorescence applications.
Implementation Method 1
utilize, for light emitting, energy of the exciton generated as a result of recombination of the electron injected from the cathode and the hole injected from the anode in the organic layer
Implementation Method 2
by using phosphorescence emitting materials
Data Source
AI summary
A charge transporting material which allows for a low driving voltage and is superior in luminous efficiency and durability is provided. The charge transporting material comprising a compound represented by any one of the general formula (1-1) to (1-3) wherein R111 to R114, R121 to R125 and R131 to R135, L111 to L113, and L121 to L123 are as defined in the specification. Ar111 to Ar113 represent a substituent represented by any one of the general formulae (3-1) to (3-3); * represents a binding position to L121 to L123; and R311, R312, R321 to R325 and R331 to R335 are as defined in the specification: