Volatile Wetting Agents for Organic Semiconductor Ink Formulation
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Solution Overview
Problem
Existing methods for preparing organic electronic devices, such as OPV cells and OLEDs, face challenges with the low solubility of organic semiconductor materials, leading to high solvent usage and inefficiencies in film formation and layer adhesion, particularly with conventional surfactants which can react with the OSC materials.
Innovation Solution
A composition comprising organic semiconducting compounds, organic solvents, and volatile wetting agents with specific properties to decrease surface tension, selected to avoid chemical reaction with OSC materials and improve film homogeneity and printing efficiency, using volatile agents that evaporate without damaging the OSC materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional surfactants are used to reduce solvent de-wetting and increase dry film levelness, then film formation improves, but the surfactants react with OSC materials and require high amounts in relation to OSC material
Solution Approach 1:
The patent introduces a specific class of surfactants (polyethylene glycol derivatives with molecular weight 200-2000) as intermediary substances that mediate between the solvent and OSC material. These surfactants reduce surface tension and improve wetting without chemically reacting with the OSC, solving the contradiction between film formation quality and chemical compatibility.
Solution Approach 2:
The patent changes the molecular weight parameter of the surfactant to a specific range (200-2000) and controls the surfactant to OSC weight ratio (0.1:1 to 10:1). This parameter optimization allows the surfactant to effectively reduce surface tension and improve film levelness while minimizing chemical interaction with the OSC material.
2Stability of the object's composition
If high amounts of solvents are used to dissolve OSC materials, then solubility improves, but solvent de-wetting occurs and environmental concerns increase
Solution Approach 1:
The surfactant acts as a mediator between the solvent and OSC material, enabling effective dissolution at lower solvent concentrations. By reducing surface tension, the surfactant allows the solvent to wet the substrate properly and maintain film levelness, eliminating de-wetting issues while reducing the total amount of solvent required.
Solution Approach 2:
The patent changes the surface tension parameter of the composition by adding surfactant, which fundamentally alters the wetting behavior. This parameter change allows the formulation to achieve proper film formation with reduced solvent content, solving both the solubility and de-wetting problems simultaneously.
3Strength
If conventional surfactants are used to improve adhesion of layers, then adhesion improves, but the adhesion of layers formed with conventional surfactants is not critical and OE devices already show useful efficiencies
Solution Approach 1:
The patent optimizes the surfactant molecular weight parameter (200-2000) and the surfactant to OSC weight ratio (0.1:1 to 10:1) to achieve a balance between adhesion improvement and device performance. This parameter optimization ensures that adhesion is sufficient for multi-layer device printing while maintaining the reliability and efficiency of the OE devices.
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 solution enhances the efficiency, lifetime, and sensitivity of OE devices by improving film forming capabilities and reducing the impact of oxidation and water sensitivity, allowing for better multi-layer device printing and maintaining OSC material integrity.
Implementation Method 1
one or more additives that decrease the surface tension of the composition
Implementation Method 2
volatile wetting agents with specific properties to decrease surface tension, selected to avoid chemical reaction with OSC materials
Data Source
Figure 1A~2
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AI summary
The present invention relates to novel compositions comprising an organic semiconductor (OSC) and a wetting agent, to their use as inks for the preparation of organic electronic (OE) devices, especially organic photovoltaic (OPV) cells and organic light emitting diode (OLED) devices, to methods for preparing OE devices using the novel compositions, and to OE devices, especially OLED devices and OPV cells prepared from such methods and compositions. The efficiency of an OE device with the inclusion of 1% volatile surfactant was 13.5 cd/A at 100 cd/m2