Polymeric Binder Composition for OLED Ink Solubility
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Solution Overview
Problem
Existing OLED device manufacturing processes require high amounts of solvents due to low solubility of organic compounds, leading to inefficiencies and limitations in achieving high-efficiency, long-lasting, and oxidation-resistant OLED devices with homogeneous film formation.
Innovation Solution
A composition comprising organic light emitting materials with a molecular weight of up to 5000 g/mol, an inert polymeric binder with a weight average molecular weight of at least 100,000 g/mol, and organic solvents with a boiling point of at least 130 °C, used as a coating or printing ink for OLED devices, where the binder does not react chemically with the semiconducting compounds and has a weight ratio of 1:2 to 1:5 with the light emitting materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If printing techniques are used to apply active layer, then OLED devices can be manufactured, but high amounts of solvents are required due to low solubility of organic compounds
Solution Approach 1:
The patent changes the molecular weight parameter of the binder polymer from conventional low molecular weight to high molecular weight (at least 100,000 g/mol). This parameter change increases the binder's ability to dissolve and disperse organic light emitting materials, thereby reducing the total solvent amount required while maintaining printability and film formation capability.
Solution Approach 2:
The patent creates a composite material system consisting of high molecular weight binder polymer, organic light emitting materials, and reduced solvent content. This composite formulation achieves optimal balance between solubility, viscosity, and film forming properties, allowing efficient OLED manufacturing with minimized solvent usage.
2Manufacturing precision
If binding agents are used to improve film forming ability, then film quality improves, but the binder material options are limited to long lists without detailed specification
Solution Approach 1:
The patent establishes specific parameter ranges for the binder polymer: molecular weight of at least 100,000 g/mol and weight ratio to light emitting material of 1:2 to 1:5. These defined parameters simplify material selection and formulation while ensuring optimal film forming ability, eliminating the need to evaluate extensive lists of unspecified binder materials.
3Ease of manufacture
If high glass transition temperature polymers are used to process low molecular weight organic materials, then processing capability improves, but cost increases and application is limited
Solution Approach 1:
The patent defines a moderate glass transition temperature range (0 to 150°C) for the binder polymer, which is lower than conventional high Tg polymers. This parameter change maintains adequate processing capability for low molecular weight organic materials while significantly reducing cost and expanding application versatility to include a broader range of OLED materials and device types.
Data Source
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AI summary
The present invention relates to novel compositions comprising light emitting materials and/or charge transport materials and a polymeric binder, to their use as conducting inks for the preparation of organic light emitting diode (OLED) devices, to methods for preparing OLED devices using the novel formulations, and to OLED devices prepared from such methods and formulations.