Hole Transport Composition Preventing Luminance Quenching
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Solution Overview
Problem
There is a need for improved hole transport compositions in organic electronic devices, particularly in OLEDs, as conventional materials often result in luminance quenching and reduced device efficiency due to their low triplet energy, which affects the performance and lifetime of these devices.
Innovation Solution
A hole transport composition comprising an inert matrix polymer and at least 10% by weight of a cyclometalated iridium complex is used, which has a triplet energy equal to or higher than the emitting exciton energy, preventing luminance quenching and maintaining device efficiency and lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional hole transport materials are used, then device manufacturing is simplified, but luminance quenching occurs and device efficiency decreases
Solution Approach 1:
The patent changes the key parameter of triplet energy from low (conventional materials) to high (at least 2.1 eV, preferably at least 2.5 eV) by selecting specific host materials and iridium complexes. This parameter change prevents luminance quenching while maintaining ease of manufacture through solution processing
Solution Approach 2:
The patent creates a composite hole transport layer combining inert matrix polymer (providing structural framework) with cyclometalated iridium complex (providing high triplet energy and hole transport capability). This composite approach achieves both anti-quenching performance and manufacturability
2Device complexity
If conventional hole transport materials are used, then device structure is simplified, but device lifetime is reduced
Solution Approach 1:
The patent changes the triplet energy parameter to at least 2.1 eV (preferably at least 2.5 eV) to prevent quenching of phosphorescent emitters, thereby extending device lifetime while maintaining simplified device structure with standard OLED layers
Solution Approach 2:
The patent uses solution-processable materials that can be deposited as thin films, creating a lightweight hole transport layer that prevents quenching without requiring complex multi-layer structures, thus extending lifetime without increasing complexity
3Loss of energy
If high triplet energy materials are used to prevent luminance quenching, then device efficiency is improved, but material selection and processing becomes more complex
Solution Approach 1:
The patent changes the triplet energy parameter to at least 2.1 eV (preferably at least 2.5 eV) to prevent luminance quenching and improve device efficiency, while using solution-processable materials that simplify fabrication compared to vacuum deposition methods
Solution Approach 2:
The patent replaces complex vacuum deposition processes with solution processing methods, allowing high triplet energy iridium complexes to be deposited from solution, thereby improving efficiency without significantly increasing device complexity
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 the cyclometalated iridium complex with a high triplet energy in conjunction with an inert matrix polymer enhances the performance of OLEDs by preventing luminance quenching and extending the device's operational lifetime, while maintaining high efficiency across various concentrations of the iridium compound.
Implementation Method 1
the organic layer emits light through the light-transmitting electrical contact layer upon application of a voltage across the electrical contact layers
Implementation Method 2
which has a triplet energy equal to or higher than the emitting exciton energy, preventing luminance quenching
Data Source
AI summary
There is provided a hole transport composition including (a) an inert matrix polymer and (b) at least 10% by weight, based on the total weight of the composition, of a cyclometalated iridium complex.