Inkjet Printing Organic Electronic Pixels with Solvent Boiling Point Differential
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Solution Overview
Problem
Existing methods for forming organic electronic (OE) devices via inkjet printing face challenges in achieving homogeneous deposition and good device performance due to the complexity of solvent selection and the negative effects of solvent vapor on adjacent pixels.
Innovation Solution
A method for forming organic OE elements with at least two different pixel types, where one pixel type uses a polymeric material with a molecular weight of ≥10,000 g/mol, and the other uses low molecular weight compounds with a molecular weight of ≤5,000 g/mol, with solvents A and B having distinct boiling points, ensuring effective ink deposition and uniform layer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different solvents are used for depositing different layers in different pixels, then the deposition flexibility and material compatibility are improved, but the solvent vapor from one pixel affects adjacent pixels causing film formation damage, material precipitation, or de-wetting
Solution Approach 1:
The substrate is divided into different pixel regions (first pixel type and second pixel type) that are processed separately with different solvents. Each pixel type has its own solvent system, preventing cross-interference during deposition and drying processes.
Solution Approach 2:
Different solvent systems are applied to different local regions (pixel types) based on their specific material requirements. The first pixel type uses solvent A optimized for polymeric materials, while the second pixel type uses solvent B optimized for low molecular weight compounds, allowing each region to have optimal local properties.
2Stability of the object's composition
If polymeric materials with high molecular weight are used, then the film formation and layer stability are improved, but the processing difficulty and solvent selection complexity increase
Solution Approach 1:
The invention specifies precise molecular weight ranges for different material types (polymeric materials with Mw ≥10,000 g/mol vs. low molecular weight compounds with Mw ≤5,000 g/mol) and corresponds each to specific solvent systems. This parameter-based classification simplifies the selection process despite the complexity of the materials.
Solution Approach 2:
Solvents act as intermediaries that facilitate the processing of different molecular weight materials. Solvent A is specifically suited for polymeric materials, while solvent B is suited for low molecular weight compounds, enabling proper dissolution and film formation without direct complex interactions between the diverse materials.
3Manufacturing precision
If inkjet printing is used for deposition, then the position precision and ink volume control are improved, but the homogeneous deposition and device performance become difficult to achieve due to multiple parameters
Solution Approach 1:
The invention establishes specific parameter ranges for materials (molecular weight) and solvents (boiling point differences of at least 10°C) that optimize the inkjet printing process. These parameter specifications ensure homogeneous deposition by controlling drying behavior and material distribution, building upon the inherent precision of inkjet printing.
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
This method prevents negative solvent vapor effects between pixels, enabling the formation of uniform and well-defined organic layers with improved efficiency, lifetime, and performance of OE devices.
Implementation Method 1
at least one layer of pixel A is deposited by applying an ink A containing at least one, preferably one organic functional material A and at least one solvent A by a printing process
Implementation Method 2
the boiling point of solvent B with the highest boiling point in ink B has a boiling point, which is at least 10° C. higher than the boiling point of solvent A with the highest boiling point in ink A
Data Source
AI summary
The present invention relates to a method for forming an organic element of an electronic device having at least two different pixel types including a first pixel type (pixel A) and a second pixel type (pixel B), —wherein at least one layer of pixel A is deposited by applying an ink A containing at least one organic functional material A and at least one solvent A by a printing process, —wherein at least one layer of pixel B is deposited by applying an ink B containing one or more organic functional material B and at least one solvent B by a printing process, —wherein the at least one organic functional material A is a polymeric material having a molecular weight Mw of ≥10,000 g/mol, —wherein the one or more organic functional material B are low molecular weight compounds having a molecular weight of ≤5,000 g/mol, and—wherein at least one solvent A and at least one solvent B are different, characterized in that the boiling point of solvent B with the highest boiling point in ink B has a boiling point, which is at least 10° C. higher than the boiling point of solvent A with the highest boiling point in ink A.