OLED White Light Emission via Electron Transport Layer Integration
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Solution Overview
Problem
Existing organic light-emitting diode (OLED) devices face challenges in achieving white light emission with improved efficiency, as they often require multiple layers for optimal performance, which complicates the fabrication process and reduces device performance when using single or dual emissive layers.
Innovation Solution
An OLED device architecture is introduced, where the emissive layer comprises at least one electroluminescent material, and the electron transport layer includes a vapor-deposited electron transport material with a higher concentration of a second electroluminescent material adjacent to the emissive layer, allowing for white light emission with separate optimization of blue efficiency, thereby simplifying the structure while maintaining high performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multiple layers are used for optimal OLED performance, then device efficiency is improved, but fabrication process complexity increases
Solution Approach 1:
The patent combines the electron transport layer and the second electroluminescent material into a single integrated layer, eliminating the need for separate layers while maintaining their respective functions. This merging reduces fabrication complexity while preserving device efficiency.
Solution Approach 2:
The electron transport layer is designed to serve dual functions: electron transport and light emission through the incorporated second electroluminescent material. This multi-functionality reduces the total number of layers needed in the device structure.
2Device complexity
If a single emissive layer is used, then fabrication process is simplified, but device performance deteriorates
Solution Approach 1:
The patent implements spatial variation in electroluminescent material concentration within the electron transport layer, with higher concentration adjacent to the emissive layer and lower concentration toward the cathode. This local quality variation enables optimized blue emission where needed while maintaining overall device performance.
Solution Approach 2:
The patent transitions from a uniform single-layer structure to a functionally differentiated structure by introducing concentration gradients and functional zones within the electron transport layer, effectively adding a compositional dimension to the design.
3Loss of energy
If blue emission is optimized separately, then power efficacy is improved, but device structure becomes more complex
Solution Approach 1:
The patent merges the blue emission function into the electron transport layer by incorporating the second electroluminescent material, allowing separate optimization of blue emission without adding independent structural layers.
Solution Approach 2:
The electron transport layer is designed to simultaneously perform electron transport and blue light emission functions, enabling independent optimization of blue emission characteristics while maintaining the layer's primary transport function.
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 configuration enhances the efficiency and longevity of the OLED device by allowing separate optimization of blue emission, resulting in improved power efficacy and a cooler white temperature, while reducing the complexity of the fabrication process.
Implementation Method 1
the electron transport layer is a vapor-deposited layer comprising at least one electron transport material and at least one second electroluminescent material
Implementation Method 2
the electron transport layer is a vapor-deposited layer
Data Source
AI summary
There is provided an organic electronic device including an anode, a hole transport layer, an emissive layer, an electron transport layer, and a cathode. The emissive layer includes at least one first electroluminescent material and the electron transport layer includes at least one electron transport material and at least one second electroluminescent material. The second electroluminescent material has a concentration that is greater adjacent the emissive layer. The device has white light emission.