White OLED Double-Layer Structure for Blue Efficiency
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Solution Overview
Problem
Manufacturing a white organic light emitting device with high efficiency and balanced red, green, and blue emissive layers is challenging due to the complexity of the fabrication process and the lower light emission efficiency of blue emissive layers compared to red and green layers.
Innovation Solution
A white organic light emitting device is designed with a double-layer structure, where both emissive layers include a blue emissive layer, along with intermediate layers for charge injection and transport, and a blocking layer for color tuning, to enhance light emission efficiency and simplify the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a stacked structure with red, green and blue emissive layers is used to achieve balanced white light emission, then color balance is improved, but manufacturing complexity and process difficulty increase
Solution Approach 1:
The patent merges the blue emissive layer function into both the first and second emissive layers, creating a symmetric double-layer structure. This combining approach simplifies the fabrication process by reducing the number of distinct emissive layer types that need to be manufactured and assembled, while still achieving balanced white light emission through the coordinated operation of the two emissive layers with intermediate charge-injecting layers
2Illumination intensity
If blue emissive layers are used in the stacked structure, then white light emission is achieved, but light emission efficiency decreases
Solution Approach 1:
The patent introduces intermediate charge-injecting layers between the first and second emissive layers to improve charge balance and injection efficiency. These intermediary layers facilitate better electron and hole transport to the blue emissive layers, thereby enhancing their light emission efficiency and reducing energy loss while maintaining white light emission
3Loss of energy
If intermediate charge-injecting layers are inserted between emissive layers to increase quantum efficiency, then light emission efficiency is improved, but fabrication process complexity increases
Solution Approach 1:
The patent segments the device into two symmetric emissive layers with intermediate charge-injecting layers positioned between them. This segmentation allows the charge-injecting layers to be integrated into a modular structure that can be fabricated using sequential deposition processes, managing complexity through systematic division of functional zones while improving quantum efficiency
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 double-layer structure improves light emission efficiency by addressing the lower efficiency of blue emissive layers and reduces manufacturing complexity, while the blocking layer facilitates accurate color tuning, resulting in a more efficient and cost-effective white organic light emitting device.
Implementation Method 1
When a voltage is applied between the cathode and the anode, light generated from the organic emissive layer is emitted through the anode
Data Source
AI summary
A white organic light emitting device includes: an anode formed on a substrate; a first emissive layer, in which a first sub-emissive layer and a second sub-emissive layer are stacked, formed on the substrate; a second emissive layer, in which a third sub-emissive layer and a fourth sub-emissive layer are stacked, formed on the first emissive layer; a first intermediate layer supplying electrons to the first emissive layer and a second intermediate layer supplying holes to the second emissive layer, wherein the first and second intermediate layers are formed between the first emissive layer and the second emissive layer; and a cathode formed on the second emissive layer.