Function Layer Ink Mixed Solvent System for Uniform Luminescent Layers
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Solution Overview
Problem
Low-molecular-weight luminescent materials used in light-emitting elements tend to aggregate during the formation of luminescent layers, leading to non-uniform thickness and emission failures due to intermolecular interactions, making it difficult to achieve desired optical properties with high yield.
Innovation Solution
A function layer ink is developed containing macromolecular or low-molecular-weight materials with a mixed solvent system, where solvent A has a viscosity of 0.01 to 0.05 Pa·s and solvent B has a lower viscosity and boiling point, allowing for controlled evaporation to reduce aggregation and ensure uniform layer thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If low-molecular-weight luminescent materials are used in the luminescent layer, then the material can be effectively deposited by liquid coating processes, but the material tends to aggregate due to intermolecular interaction, resulting in non-uniform layer thickness and emission failures
Solution Approach 1:
A macromolecular material is introduced as an intermediary substance in the ink composition. This macromolecular material acts as a mediator that prevents aggregation of low-molecular-weight luminescent materials through intermolecular interactions, while allowing the luminescent material to be effectively deposited by liquid coating processes. The macromolecular material serves as a protective intermediary that maintains material dispersion and layer uniformity.
Solution Approach 2:
The ink is formulated as a composite material system containing both low-molecular-weight luminescent materials and macromolecular materials. This composite approach combines the advantageous properties of both material types: the low-molecular-weight materials provide luminescence functionality and ease of deposition, while the macromolecular materials prevent aggregation and ensure layer uniformity. The synergistic combination resolves the contradiction between manufacturability and manufacturing precision.
2Productivity
If the drying speed of the ink is increased to improve productivity, then the manufacturing cycle is shortened, but aggregation caused by intermolecular interaction of the function layer material increases, reducing layer uniformity
Solution Approach 1:
The macromolecular material serves as a protective intermediary that remains effective even during rapid drying processes. It prevents intermolecular aggregation of luminescent materials throughout the drying cycle, allowing productivity to be improved through faster drying without sacrificing layer uniformity. The intermediary material maintains material dispersion from wet to dry states.
Solution Approach 2:
The ink formulation parameters are optimized by incorporating macromolecular materials that alter the physical and chemical parameters of the ink system. This enables control over the drying process at different stages, allowing rapid drying to be achieved while maintaining material uniformity through the protective effect of macromolecular components throughout the parameter transition from wet to dry state.
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 use of the function layer ink results in light-emitting elements with desired optical properties and high yield, reducing aggregation and improving the uniformity and quality of the luminescent layers.
Implementation Method 1
solvent B evaporates more rapidly than solvent A when the function layer ink is dried
Implementation Method 2
the viscosity of the mixed solvent gradually increases to the viscosity of solvent A
Implementation Method 3
aggregation caused by intermolecular interaction of the function layer material becomes slow, and is thus reduced
Data Source
AI summary
A function layer ink used for forming a function layer by a liquid coating process contains a function layer material containing a macromolecular material or a low-molecular-weight material, and a mixed solvent containing solvent A and solvent B. Solvent A has a viscosity in the range of 0.01 to 0.05 Pa·s, and solvent B has a viscosity of less than 0.01 Pa·s and a lower boiling point than solvent A. The mixed solvent has a viscosity of less than 0.02 Pa·s and a boiling point in the range of 200 to 350° C., and contains 0.1% to 10% by weight of solvent A.