Ink Composition for Light Emitting Devices
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Solution Overview
Problem
Existing light emitting devices require multiple processes to form multiple electron transport layers, which can be complex and inefficient, and there is a need for a method to simplify the manufacturing process while maintaining the quality of thin film formation and electron mobility.
Innovation Solution
An ink composition containing a first and second solvent with different boiling points and vapor pressures, along with first and second electron transport materials with distinct ligands, is used to form multiple electron transport layers in a single process, allowing for the formation of a mixed region between the layers with varying concentrations of the materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple separate processes are used to form multiple electron transport layers, then each layer can be formed with controlled composition, but the manufacturing process becomes complex and inefficient
Solution Approach 1:
The patent combines multiple electron transport layers into a single mixed layer by incorporating multiple electron transport materials (e.g., ZnO and SnO2) and their respective ligands into one ink composition. This allows both layers to be formed simultaneously in a single deposition process, reducing manufacturing complexity while maintaining compositional control through careful selection of material ratios and ligand types.
Solution Approach 2:
The invention uses composite materials by combining different electron transport materials (ZnO, SnO2) with different ligands (acetic acid, 2-methoxyethoxy ethanethiol) in a single ink formulation. The composite nature of the ink allows different materials to be deposited together while maintaining their individual properties and forming distinct functional zones within the same layer structure.
2Reliability
If multiple separate processes are used to form multiple electron transport layers, then each layer can be optimized for electron mobility, but the manufacturing time and efficiency decrease
Solution Approach 1:
The patent merges the formation of multiple electron transport layers into a single deposition process by using an ink composition containing multiple electron transport materials with different ligands. This simultaneous formation approach maintains the electron mobility benefits of multiple optimized layers while dramatically improving manufacturing efficiency by eliminating the need for sequential deposition steps.
3Ease of manufacture
If a single ink composition is used to form multiple electron transport layers, then the manufacturing process is simplified, but the control over individual layer composition becomes difficult
Solution Approach 1:
The patent applies local quality by creating different functional zones within the electron transport layer through the use of multiple materials with different ligand lengths. The shorter ligand materials (e.g., ZnO with acetic acid) and longer ligand materials (e.g., SnO2 with 2-methoxyethoxy ethanethiol) self-organize to form distinct regions with different electron transport characteristics, allowing compositional control at the local level while maintaining simplicity in the overall manufacturing process.
4Reliability
If different ligands with different lengths are used in electron transport materials, then the electron transport performance is enhanced, but the ink composition complexity increases
Solution Approach 1:
The patent utilizes parameter changes by varying the ligand length parameter across different electron transport materials. The ink composition includes materials with short ligands (2 atoms or less, e.g., acetic acid) and materials with long ligands (5 or more atoms, e.g., 2-methoxyethoxy ethanethiol). This parameter variation enhances electron transport performance by creating optimal conditions for electron mobility while the differences in ligand length provide a systematic way to manage composition complexity.
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 approach simplifies the manufacturing process, improves thin film uniformity, and enhances electron mobility and luminous efficiency by forming multiple electron transport layers with a single ink composition, reducing the complexity of separate layer formation processes.
Implementation Method 1
heating the ink composition to evaporate the first solvent and form the first electron transport layer including the first electron transport material, and heating the ink composition to evaporate the second solvent and form a second electron transport layer including the second electron transport material
Data Source
AI summary
An ink composition includes a first solvent, a second solvent, a first electron transport material and a second electron transport material. The first electron transport material includes a metal oxide, and a ligand disposed on a surface of the metal oxide. The second electron transport material includes a metal oxide, and a ligand positioned on a surface of the metal oxide. The ligand of the first electron transport material and the ligand of the second electron transport material are different from each other. A difference in a length of the ligand of the first electron transport material and a length of the ligand of the second electron transport material is three or more atoms.