Organic EL Functional Layer Solution Composition for Film Formation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for manufacturing organic EL elements using a liquid phase process face challenges with film formation failures and reduced luminescent efficiency due to aggregation of low molecular materials, especially when trying to produce multiple colors on a substrate, and require improved molecular weight ratios and solvent properties for stable film formation.
Innovation Solution
A method involving a solution with a low molecular material of 10,000 or less and a high molecular material with a weight average molecular weight between 10,000 to 300,000, applied using a liquid droplet discharging method, where the high molecular material has a smaller band gap than the low molecular material, and a good solvent with a boiling point of 200°C or higher is used to enhance viscosity and discharge stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low molecular material is used in the liquid phase process to improve luminescent efficiency and lifetime, then the luminescent performance is improved, but aggregation occurs during selective application causing film formation failures
Solution Approach 1:
The patent combines low molecular materials (for luminescent efficiency) with high molecular materials (for film formation stability) to create a composite solution. The high molecular material acts as a matrix that prevents aggregation of the low molecular material during selective application, while the low molecular material provides the desired luminescent properties. This composite approach resolves the contradiction between luminescent performance and film formation uniformity.
Solution Approach 2:
The patent optimizes the molecular weight parameters of both low molecular and high molecular materials, as well as their mixing ratios and solvent properties (boiling point ≥200°C). By carefully controlling these parameters, the solution achieves both good discharge properties (from low molecular material) and stable film formation without aggregation (from high molecular material).
2Reliability
If the molecular weight of the low molecular material is reduced to improve luminescent efficiency, then the luminescent performance is enhanced, but the solution viscosity decreases making selective application difficult
Solution Approach 1:
The patent creates a composite system where high molecular materials provide the necessary viscosity and discharge stability, while low molecular materials provide luminescent efficiency. The high molecular material acts as a carrier that enables stable liquid droplet discharge even when the low molecular material concentration is optimized for luminescence.
3Ease of manufacture
If a good solvent with high boiling point is used to increase viscosity and improve discharge stability, then the discharge properties are improved, but the drying time increases
Solution Approach 1:
The patent selects solvents with boiling points of 200°C or higher to ensure adequate viscosity for stable liquid droplet discharge. While this increases drying time compared to lower boiling point solvents, the high molecular material in the composite system helps maintain film formation quality throughout the extended drying process, preventing aggregation even with prolonged exposure.
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 reduces film formation failures, achieves excellent luminescent efficiency and lifetime, and allows for the production of organic EL elements with targeted chromaticity by preventing energy absorption in the high molecular material, ensuring stable adhesion and discharge properties.
Implementation Method 1
the weight average molecular weight of the high molecular material is from 10,000 to 300,000... a good solvent with a boiling point of 200°C or higher is used to enhance viscosity and discharge stability
Implementation Method 2
An organic electro-luminescence (EL) element has a functional layer including a luminescence material consisting of an organic compound between an anode and a cathode
Implementation Method 3
a good solvent with a boiling point of 200°C or higher is used... in a dry process of the solution which is applied
Data Source
AI summary
An organic EL element with a functional layer including at least a hole injection layer, a hole transport layer, and a luminescence layer laminated from a pixel electrode side in order between a pixel electrode as an anode and a counter electrode as a cathode, and a method of manufacturing the organic EL element has a forming process by applying a solution including a low molecular material and a high molecular material to at least one layer among the hole injection layer, the hole transport layer, and luminescence layer, in which the molecular weight of low molecular material is 10,000 or less and the molecular weight of high molecular material is 10,000 to 300,000, and in which a mixing ratio of low molecular material is 10 wt % to 90 wt % with respect to the weight of low molecular material and high molecular material included in the solution.