OLED Buffer Layer Inkjet Process Interface Resistance
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Solution Overview
Problem
The existing electroluminescence display apparatuses face issues with reduced performance, efficiency, and lifetime due to interface problems between the light emitting layers formed through different deposition processes, particularly between the inkjet-deposited first light emitting layer and the deposition-formed second light emitting layer.
Innovation Solution
Incorporating a buffer layer formed through an inkjet process on the first light emitting layer, which can be made of organic materials, to enhance device performance and minimize interface issues with the second light emitting layer formed via deposition, thereby reducing resistance and improving emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the second light emitting layer is formed through deposition process on the first light emitting layer formed through inkjet process, then the device structure is completed, but interface problems occur causing reduced efficiency and lifetime
Solution Approach 1:
An organic buffer layer is introduced as an intermediary between the inkjet-deposited first light emitting layer and the deposition-formed second light emitting layer. This buffer layer serves as a mediator that improves interface compatibility, reduces interface defects, and enhances the overall reliability of the device structure while maintaining ease of manufacture through sequential deposition processes.
2Adaptability or versatility
If the light emitting layers are formed through different deposition processes (inkjet and deposition), then manufacturing flexibility is achieved, but interface defects occur reducing device lifetime
Solution Approach 1:
The organic buffer layer acts as a transitional intermediary that bridges two different deposition processes (inkjet and deposition). It accommodates the differences in material deposition methods by providing a compatible interface layer, thereby maintaining manufacturing process flexibility while significantly improving device lifetime by reducing interface-related degradation.
Solution Approach 2:
The buffer layer changes the material composition parameter at the interface between the two light emitting layers. By introducing an organic material layer with specific properties that are compatible with both inkjet-deposited and deposition-formed layers, the interface parameters are optimized to prevent defects and extend device operational lifetime.
3Device complexity
If no buffer layer is provided between the first and second light emitting layers, then device complexity is reduced, but current efficiency decreases due to interface resistance
Solution Approach 1:
The organic buffer layer serves as a conductive intermediary that reduces interface resistance between the two light emitting layers. Although it adds a layer to the device structure, the buffer layer's primary function is to improve charge transport across the interface, thereby reducing energy loss and improving current efficiency without significantly increasing overall device complexity.
Data Source
AI summary
Discussed is an electroluminescence display apparatus for preventing the performance, efficiency, and lifetime of a device from being reduced. The electroluminescence display apparatus includes a substrate including an active area including a plurality of pixels, a circuit element layer disposed on the substrate, a first electrode disposed on the circuit element layer, an auxiliary electrode disposed on the circuit element layer and spaced apart from the first electrode, a first light emitting layer disposed on the first electrode, a buffer layer disposed on the first light emitting layer, a second light emitting layer disposed on the buffer layer and the auxiliary electrode, and a second electrode disposed on the second light emitting layer. In the electroluminescence display apparatus, since the buffer layer is formed on the first light emitting layer through an inkjet process, the buffer layer can be provided on only the first light emitting layer, and thus, the buffer layer can be formed of an organic material, thereby enhancing the device performance of a blue pixel.