Mixed Powder for Organic EL Devices Stabilizing Vapor Deposition
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Solution Overview
Problem
The premix technique for forming organic electroluminescence (EL) device films faces challenges in maintaining a consistent mixing ratio over time, especially when one component has a significantly higher content ratio than the other, leading to fluctuations in the vapor-deposited film composition and reduced yield.
Innovation Solution
A mixed powder comprising a first and second organic compound, where the molar concentration of the second compound is between 0 and 20% of the total, and the temperature difference between the compounds during vapor deposition is maintained between -20°C and 40°C, ensuring stable vaporization and consistent film formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a premix technique is used to simplify the vapor deposition process, then the fabrication process becomes simpler and manufacturing burden is reduced, but the component ratio in the vapor-deposited film fluctuates and manufacturing precision deteriorates
Solution Approach 1:
The patent applies parameter changes by establishing specific relationships between vaporization rates, molecular weights, and content ratios of the first and second compounds. By controlling the temperature difference between the vaporization rates of the two compounds within a specific range and satisfying the mathematical relationship involving vapor pressure, molecular weight, and molar concentration, the patent achieves stable component ratios in the vapor-deposited film while using a simplified premix technique.
Solution Approach 2:
The patent introduces dynamic control by adjusting the temperature difference between compounds during vapor deposition. Rather than using fixed temperatures, the method dynamically controls the temperature difference to maintain it within a specific range, allowing the system to adapt to variations in vaporization rates and maintain consistent component ratios throughout the deposition process.
2Manufacturing precision
If co-vapor deposition is used to maintain constant mixing ratio, then manufacturing precision is improved, but device complexity and manufacturing burden increase
Solution Approach 1:
The patent merges multiple vapor deposition sources into a single source by pre-mixing the first and second compounds. Instead of using separate sources for each compound as in co-vapor deposition, the invention combines both compounds in one source and controls their simultaneous vaporization through temperature difference management, thereby reducing device complexity while maintaining manufacturing precision.
Solution Approach 2:
The patent implements feedback control by continuously monitoring and adjusting the temperature difference between the first and second compounds during vapor deposition. The method ensures that the temperature difference remains within a specific range by adjusting heating conditions, creating a feedback loop that maintains stable component ratios without requiring multiple independent control systems.
3Quantity of substance
If one component has significantly higher content ratio in premix material, then the dominant component vaporizes preferentially, but the component ratio in the deposited film fluctuates and manufacturing precision deteriorates
Solution Approach 1:
The patent applies the counterweight principle by using the temperature difference between the first and second compounds to compensate for the preferential vaporization of the dominant component. The higher content component vaporizes faster, but the temperature difference control creates a compensating effect that balances the vaporization rates, ensuring stable component ratios in the deposited film despite large differences in content ratios.
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 stabilizes the component ratio in the vapor-deposited films, reducing fluctuations and improving the yield by maintaining a balanced vaporization of both compounds throughout the deposition process.
Implementation Method 1
vacuum vapor deposition process is generally used as a method of forming an organic layer constituting organic electroluminescence devices
Implementation Method 2
a film is formed by vaporizing a so-called premix material, in which a plurality of materials (organic compounds) are mixed in advance
Data Source
AI summary
A mixed powder for an organic electroluminescence device, including a first organic compound and a different second organic compound, wherein the mixed powder is solid at normal temperature and pressure, and the following formulas (1) and (2) are satisfied: 0<MOL2/(MOL1+MOL2)≤0.2 . . . (1) and −20° C.≤T1−T2≤40° C. . . . (2), wherein MOL1 [mol %] is a molar concentration of the first organic compound, MOL2 [mol %] is a molar concentration of the second organic compoundb, T1 [° C.] is a temperature of the first organic compound when P1/M11/2=0.04×{MOL1/(MOL1+MOL2)} is satisfied, T2 [° C.] is a temperature of the second organic compound when P2/M21/2=0.04×{MOL2/(MOL1+MOL2)} is satisfied, M1 [kg/mol] is the molecular weight of the first organic compound, P1 [Pa] is a vapor pressure of the first organic compound, M2 [kg/mol] is the molecular weight of the second organic compound, P2 [Pa] is a vapor pressure of the second organic compound.