Organic Electroluminescent Device Vacuum Drying Film Density
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Solution Overview
Problem
The existing solution methods for forming function layers in organic electroluminescent devices result in poor density and uniformity due to residual solvent, leading to defects and impaired energy transfer and carrier transport capabilities, especially in light-emitting layers.
Innovation Solution
A method involving vacuum drying at a constant temperature is employed to form function layers, effectively removing residual solvent and enhancing film density and carrier mobility, allowing for better energy transfer and recombination between host and guest molecules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If drying at room temperature is used to form the function layer, then the manufacturing process is simple, but residual solvent remains causing poor film density and uniformity
Solution Approach 1:
The patent changes the drying parameters from room temperature to elevated temperature (60-150°C) and introduces vacuum conditions, transforming the drying process from simple ambient drying to controlled thermal-vacuum drying. This resolves the contradiction by achieving both improved film quality through parameter optimization and maintained process simplicity through a single-step drying operation.
Solution Approach 2:
The patent employs vacuum drying environment to remove residual solvent more effectively. The vacuum conditions create an inert atmosphere that facilitates complete solvent evaporation without contamination, thereby improving film density and uniformity while keeping the manufacturing process straightforward.
2Ease of manufacture
If solution coating method is used to form the function layer, then the manufacturing process is simple, but host and guest molecules cannot merge well affecting energy transfer and carrier transport
Solution Approach 1:
The patent applies thermal energy by raising the drying temperature to 60-150°C, which provides activation energy for molecular diffusion and merging. This thermal treatment enables host and guest molecules to intermix properly, improving energy transfer and carrier transport while maintaining the simplicity of the solution coating approach.
Solution Approach 2:
The patent utilizes the phase transition of the solvent from liquid to vapor during vacuum drying. This phase change process allows sufficient time and mechanism for the host and guest molecules to diffuse and merge into a homogeneous structure, thereby improving device reliability without complicating the manufacturing process.
3Manufacturing precision
If vacuum drying at elevated temperature is used to form the function layer, then film density and solvent removal are improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent optimizes the drying parameters to a specific temperature range (60-150°C) and vacuum level, achieving effective solvent removal and film densification. By defining clear parameter boundaries, the process remains manageable and does not become excessively complex, balancing film quality with manufacturing ease.
Solution Approach 2:
The patent performs vacuum drying as a preliminary step immediately after solution coating, before any subsequent device assembly or processing. This preliminary removal of solvent prevents later complications and reduces the need for additional processing steps, thereby maintaining manufacturing simplicity while achieving high film quality.
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 method results in a smooth and dense film with improved luminous performance and extended lifetime of the organic electroluminescent device and display apparatus.
Implementation Method 1
performing a vacuum drying on the liquid material layer for the function layer to form the function layer... the organic solvent can be rapidly cleared, and can be cleared relatively completely
Implementation Method 2
when a vacuum drying is performed, since the organic solvent molecules are more vigorous when being heated, the solvent is easily volatile
Data Source
AI summary
The invention provides an organic electroluminescent device and a manufacturing method thereof, and a display apparatus. The method for manufacturing the organic electroluminescent device of the invention includes using the following to form at least one function layer: preparing a solution of a material of the function layer, and forming a liquid material layer for the function layer using the solution of the material of the function layer; performing a vacuum drying on the liquid material layer for the function layer to form function layer. In the invention, a relatively dense film is formed by performing a vacuum drying on the function layer, and the residual organic solvent is effectively removed to avoid the formation of defects, so that the film becomes smooth and dense, which increases the carrier mobility in the film and is advantageous to the transport and recombination of electrons and holes.