Organic Semiconductor Ink Formulation for High-Resolution Printing

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Solution Overview

Problem

Current methods for producing organic electronic devices, such as OLEDs and OPV cells, face challenges with high production costs, wastefulness, and limitations in achieving high resolution and large quantities due to expensive vapor techniques, and low-quality results with conventional ink-jet printing.

Innovation Solution

A composition of organic semiconducting compounds and organic solvents with specific solvent ratios and properties, allowing for high-resolution ink-jet printing by using a mixture of aromatic ether and aromatic ester solvents, enabling the production of high-quality, efficient, and long-lasting organic electronic devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If vapor techniques are used to apply the OSC layer, then high resolution is achieved, but production cost increases and production quantity is limited

Engineering Contradiction:
ImproveresolutionVSAvoidproduction quantity
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces vapor deposition techniques with ink-jet printing technology. This substitution allows for direct digital printing of organic semiconductor compounds onto substrates, enabling both high resolution patterns and scalable production. The ink-jet system uses controlled droplet deposition rather than vapor phase deposition, achieving comparable resolution while allowing larger area coverage and higher throughput.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent modifies the physical parameters of the deposition process by changing from vapor phase to liquid droplet phase. By controlling droplet size, composition, and deposition parameters, the system achieves high resolution while enabling quantitative production. The use of specific solvent mixtures with controlled evaporation rates further optimizes the printing parameters for both resolution and productivity.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional ink-jet printing techniques are used, then production cost decreases, but manufacturing precision and product quality deteriorate

Engineering Contradiction:
Improveproduction costVSAvoidresolution
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the physical parameters of ink-jet printing by using extremely small droplet sizes (below 10 pL) and optimizing solvent composition. This parameter optimization enables conventional ink-jet printers to achieve high resolution comparable to vapor techniques while maintaining the cost advantages of liquid deposition methods.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite solvent systems comprising multiple components with different evaporation rates (fast-evaporating and slow-evaporating solvents). This composite approach optimizes both the printing process and final film quality, enabling high resolution patterns while using cost-effective ink-jet equipment rather than expensive vapor deposition systems.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If droplet size is reduced below 10 pL for high resolution, then manufacturing precision improves, but process complexity and difficulty of achieving continuous reproducible printing increase

Engineering Contradiction:
ImproveresolutionVSAvoidprinting process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces specially formulated solvent mixtures as intermediaries that facilitate the use of small droplet sizes. The solvent composition (including fast and slow evaporating components) ensures proper droplet formation, spreading, and film formation even at sub-10 pL volumes, simplifying the overall printing process while maintaining high resolution.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent optimizes multiple parameters simultaneously: droplet volume (below 10 pL), solvent composition (specific ratios of fast and slow evaporating solvents), and printing conditions. This multi-parameter optimization makes the small droplet printing process reproducible and continuous, reducing the practical complexity despite the stringent requirements.

Inventive Principle:
Principle #35Parameter changes

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 enables high-resolution, cost-effective, and efficient production of organic electronic devices with improved performance, lifetime, and reduced sensitivity to water and oxidation, facilitating the use of ink-jet printing for complex structures.

Implementation Method 1

the first organic solvent has a boiling point in the range of 235 to 320°C and a relative evaporation rate (RER; based on butyl acetate = 100) of at most 0.6 and the second organic solvent has a relative evaporation rate (RER; based on butyl acetate = 100) in the range of 0.65 to 10.0

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3323159B1Composition comprising organic semiconducting compounds
Publication Date: 2023.01.04 MERCK PATENT GMBH
  • EP3323159B1 patent drawingFigure 1a~2
  • EP3323159B1 patent drawingFigure 3~4
  • EP3323159B1 patent drawing

AI summary

The present invention relates to novel composition comprising an organic semiconductor (OSC) and organic solvents. The composition comprises at least two organic solvents. Furthermore, the present invention describes the use of these compositions as inks for the preparation of organic electronic (OE) devices, especially organic photovoltaic (OPV) cells and OLED devices, to methods for preparing OE devices using the novel formulations, and to OE devices, OLED devices and OPV cells prepared from such methods and compositions.