Organic EL Device Intermediate Layer Electron Injection
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Solution Overview
Problem
Existing organic EL devices face challenges in achieving high luminous efficiency and long lifetime, particularly with blue luminescent layers formed by coating, as charge transfer between macromolecular and low-molecular-weight materials is inefficient, leading to degraded performance.
Innovation Solution
A method is introduced where a first and second luminescent layer are formed by coating, with an intermediate electron injection layer, and a third luminescent layer is formed by vapor deposition, enhancing electron injection performance and allowing smooth electron transfer, thereby improving the luminous efficiency and lifetime of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the blue luminescent layer is formed by coating to achieve easy patterning and efficient material use, then manufacturing ease is improved, but electron injection performance deteriorates due to poor charge transfer between macromolecular and low-molecular-weight materials
Solution Approach 1:
An intermediate layer is introduced between the blue luminescent layer (formed by coating) and the red/green luminescent layers (formed by vapor deposition). This intermediate layer acts as a mediator that facilitates smooth charge transfer and electron injection between the macromolecular coating material and low-molecular-weight vapor deposition material, resolving the electron injection performance issue while maintaining the manufacturing advantages of coating.
2Device complexity
If the blue luminescent layer is formed by coating to reduce manufacturing complexity, then device complexity is reduced, but luminous efficiency and lifetime deteriorate due to insufficient electron injection
Solution Approach 1:
The intermediate layer serves as a bridge between the coating-formed blue luminescent layer and vapor deposition-formed red/green luminescent layers, enabling efficient electron injection and charge transfer. This resolves the lifetime issue by ensuring proper electron injection while maintaining the manufacturing simplicity of using coating for the blue layer.
3Reliability
If the blue luminescent layer is formed by vapor deposition to improve electron injection performance, then reliability is improved, but manufacturing precision and material efficiency deteriorate compared to coating methods
Solution Approach 1:
The device is segmented into different regions with different formation methods: the blue luminescent layer is formed by coating (providing good patterning and material efficiency), while the red and green luminescent layers are formed by vapor deposition (providing good electron injection performance). The intermediate layer connects these segmented regions, allowing each part to发挥 its advantages.
4Productivity
If coating method is used for blue luminescent layer to achieve cost-effective manufacturing, then productivity is improved, but luminous efficiency deteriorates due to poor charge transfer
Solution Approach 1:
The intermediate layer acts as a mediator that enables efficient charge transfer between the coating-formed blue luminescent layer and the vapor deposition-formed red/green luminescent layers. This resolves the luminous efficiency issue by ensuring proper electron injection and charge transfer, while maintaining the productivity advantages of using coating for the blue layer.
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 structure ensures high luminous efficiency and long lifetime for the organic EL device, bringing blue luminescent characteristics closer to those of red and green layers, enabling the display of high-quality images.
Implementation Method 1
an intermediate layer having electron injection performance is formed on the first luminescent layer and the second luminescent layer
Implementation Method 2
a first luminescent layer emitting first color light is formed over a first anode disposed on a substrate by coating
Implementation Method 3
a third luminescent layer emitting third color light is formed over the intermediate layer and a third anode disposed on the substrate by vapor deposition
Implementation Method 4
light is emitted when the electrons and the holes are recombined to each other
Data Source
AI summary
In a method for manufacturing an organic EL device, a first luminescent layer emitting first color light is formed over a first anode disposed on a substrate by coating. A second luminescent layer emitting second color light is formed over a second anode disposed on the substrate. An intermediate layer having electron injection performance is formed on the first luminescent layer and the second luminescent layer. A third luminescent layer emitting third color light is formed over the intermediate layer and a third anode disposed on the substrate by vapor deposition. A cathode is formed on the third luminescent layer.