Solvent Mixture for Organic Electronic Device Formulations
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Solution Overview
Problem
Existing solvents for organic electronic devices, particularly for inkjet printing of OLEDs, face challenges such as low efficiency, short lifetime, toxicity, and environmental concerns due to slow solubilization and complex parameter management, leading to suboptimal device performance and environmental issues.
Innovation Solution
A formulation comprising a mixture of two different solvents, where the first solvent has a lower boiling point and higher viscosity than the second, optimized for inkjet printing, allowing for rapid and uniform deposition of organic semiconductor layers with improved layer properties and environmental acceptability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional solvents are used for inkjet printing of OLEDs, then the solubilization process is slow requiring extensive effort, but the solvent may provide adequate device performance
Solution Approach 1:
The patent changes the chemical parameters of the solvent system by introducing a specific mixture of cyclopentanone and cyclohexanone in controlled ratios (1:4 to 4:1). This parameter change enables rapid solubilization of organic semiconductor materials while providing optimal viscosity and surface tension for inkjet printing, thereby improving productivity without excessive time investment.
Solution Approach 2:
The patent employs a composite solvent system combining cyclopentanone and cyclohexanone in specific proportions. This composite approach leverages the complementary properties of both solvents: cyclopentanone provides rapid solubilization and appropriate viscosity, while cyclohexanone contributes to stable film formation and device performance, achieving both fast preparation and high-quality results.
2Reliability
If prior art solvents are used for OLED fabrication, then the device efficiency and lifetime are low, but the solubilization process is simpler
Solution Approach 1:
The patent optimizes critical parameters including solvent composition ratios (cyclopentanone:cyclohexanone from 1:4 to 4:1), organic semiconductor concentration (0.1-10 wt%), and processing conditions (temperature, humidity, deposition speed). These parameter optimizations simultaneously improve device efficiency and lifetime while maintaining manufacturing simplicity through a straightforward one-step inkjet printing process.
Solution Approach 2:
The patent replicates and refines successful elements from conventional solvent systems while introducing improvements. By copying the effective solubilization mechanism of traditional solvents and enhancing it with the cyclopentanone-cyclohexanone mixture, the patent achieves better device performance without fundamentally complicating the manufacturing process.
3Object-affected harmful factors
If conventional solvents are used for inkjet printing, then toxic environmental issues arise, but the deposition process is well-established
Solution Approach 1:
The patent replaces persistent, toxic conventional solvents with biodegradable cyclic ketones (cyclopentanone and cyclohexanone) that have low environmental impact. These substitute solvents maintain the necessary functional properties for inkjet printing while being environmentally benign, allowing disposal without severe ecological consequences.
Solution Approach 2:
The patent changes the chemical composition parameters to use environmentally friendly cyclic ketones instead of traditional toxic solvents. This parameter substitution maintains adequate viscosity, surface tension, and solubilization capabilities while eliminating toxicity concerns, thus preserving the established inkjet printing process while improving environmental safety.
4Manufacturing precision
If a single solvent is used for organic semiconductor deposition, then the formulation is simpler, but the layer uniformity and device performance are suboptimal
Solution Approach 1:
The patent employs a composite solvent formulation of cyclopentanone and cyclohexanone in specific ratios (1:4 to 4:1). This composite system provides synergistic effects: cyclopentanone ensures rapid solubilization and optimal viscosity for inkjet droplet formation, while cyclohexanone promotes uniform film formation and enhances device performance, achieving superior layer uniformity through compositional synergy.
Solution Approach 2:
The patent assigns different functional roles to each solvent component based on their local properties: cyclopentanone primarily handles solubilization and viscosity control, while cyclohexanone focuses on film formation stability and device performance enhancement. This functional differentiation within the formulation achieves optimal layer uniformity through specialized contributions from each component.
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 solvent mixture enables efficient, rapid, and uniform deposition of organic semiconductor layers, enhancing the performance and lifetime of OLEDs while being less toxic and more environmentally friendly, facilitating high-quality and cost-effective printing processes.
Implementation Method 1
a first organic solvent exhibits a lower boiling point than a second organic solvent
Implementation Method 2
formulations comprising at least one organic functional material, and organic solvents
Data Source
Figure 1(a)~1(b)
Figure 1(c)
AI summary
The present invention relates to formulations for the preparation of organic electronic devices which comprise at least one organic functional material and a mixture of at least two different solvents wherein a first organic solvent exhibits a lower boiling point than a second organic solvent and said first organic solvent exhibits a higher viscosity than said second organic solvent.