Amine-Group Polymers for OLED Hole Transport Layer Stability
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Solution Overview
Problem
Existing organic electroluminescent devices (OLEDs) face challenges in achieving improved efficiency and longevity due to the lack of suitable materials for the hole-transporting layer that can be processed from solution without damaging previously applied layers, and that match the functionalities of adjacent layers effectively.
Innovation Solution
Development of polymers with repeat units containing aryl-bisamine groups, which are incorporated into the hole-transporting layer to enhance the efficiency and properties of OLEDs by being either conjugated, semi-conjugated, or non-conjugated, allowing for better layer integration and stability during the multilayer application process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple layers are applied from solution in multilayer OLED systems, then the device can be manufactured with improved processability and cost-effectiveness, but the previously applied layers may be destroyed or damaged by the subsequent solution application
Solution Approach 1:
The patent applies preliminary action by performing crosslinking of the first layer before applying the second layer from solution. This pre-treatment renders the first layer insoluble and resistant to subsequent processing steps, allowing multiple layers to be applied from solution without damaging previously applied layers. The crosslinking is performed in-situ within the OLED structure, enabling sequential layer deposition while maintaining layer integrity.
2Productivity
If the hole-transporting layer material is optimized for improved efficiency, then the OLED performance increases, but the compatibility and stability with adjacent layers during multilayer application may be compromised
Solution Approach 1:
The patent applies parameter changes by modifying the chemical and physical properties of the hole-transporting layer through crosslinking. This transformation changes the layer from a soluble, processable material to an insoluble, stable network structure. The crosslinked structure maintains the functional properties needed for high efficiency while gaining resistance to solvent attack and improved stability during subsequent layer application processes.
Solution Approach 2:
The patent employs composite materials by creating a crosslinked polymer network within the hole-transporting layer. This crosslinked structure combines the beneficial properties of the original polymer material with enhanced mechanical and chemical stability. The composite crosslinked structure provides both the functional performance needed for high efficiency and the structural stability required for compatibility during multilayer processing.
Data Source
AI summary
The invention relates to polymers having at least one repeating unit of the following formula (I): wherein Ar1, Ar2, Ar3 and Ar4, R and X, and a, b, c, d, e and f can have the meanings defined in claim 1, to processes for the preparation thereof and to the use thereof in electronic or optoelectronic devices, in particular in organic electroluminescent devices, so-called OLEDs (OLED═Organic Light Emitting Diodes). The present invention also relates to electronic or optoelectronic devices, in particular organic electroluminescent devices, which contain said polymers.