Organic Light-Emitting Device Host Material Merging
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Solution Overview
Problem
Existing organic light-emitting devices face challenges in achieving a balance between good color gamut, high luminous efficiency, and long lifespan, often resulting in complex structures that complicate the fabrication process and increase production costs.
Innovation Solution
The use of a single host material for the red organic light-emitting layer and multiple host materials for the yellow-green layer, where the materials of the electron transport and hole transport layers are shared, simplifies the structure and enhances interfacial charge movement, allowing for a simpler fabrication process while maintaining high luminous efficiency and color gamut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple host materials are used for the yellow-green organic light emitting layer to achieve good color gamut and high luminous efficiency, then the device performance is improved, but the structure becomes complicated and the fabrication process becomes complex
Solution Approach 1:
The patent merges the host material functions by making the yellow-green organic light emitting layer include both the hole transport layer material and electron transport layer material as host materials. This combining approach achieves good color gamut and high luminous efficiency through multiple host materials while avoiding the need for separate additional host material layers, thus simplifying the overall device structure and fabrication process
Solution Approach 2:
The patent applies multi-functionality by designing the yellow-green organic light emitting layer to serve multiple purposes: it acts as the light emitting layer while simultaneously incorporating materials from both the hole transport layer and electron transport layer as host materials. This universal design allows a single layer to fulfill multiple functional roles, improving device performance without increasing structural complexity
2Reliability
If additional host materials are used for the organic light emitting layers to improve color gamut and luminous efficiency, then the device performance is improved, but the number of materials increases and production cost rises
Solution Approach 1:
The patent makes the existing hole transport layer material and electron transport layer material serve dual functions by incorporating them as host materials in the yellow-green organic light emitting layer. This eliminates the need for additional dedicated host materials, reducing the total number of materials required while maintaining high device performance
Solution Approach 2:
The patent combines the functional roles of different materials by making the yellow-green organic light emitting layer include both hole transport layer material and electron transport layer material as host materials. This merging approach reduces material inventory requirements and simplifies the material system while achieving good color gamut and high luminous efficiency
3Reliability
If the organic light emitting layer and transport layers use different materials to maintain functional independence, then the device reliability is maintained, but the interfacial charge movement is hindered
Solution Approach 1:
The patent changes the material composition parameter of the yellow-green organic light emitting layer by incorporating materials from both the hole transport layer and electron transport layer as host materials. This parameter change improves interfacial charge movement efficiency while maintaining device reliability through proper material selection and interface design
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 approach results in an organic light-emitting device with improved color gamut, luminous efficiency, and extended lifespan, while reducing the number of materials needed and simplifying the fabrication process, thereby increasing production yield.
Implementation Method 1
Electrons and holes are injected into the organic light emitting layer from the two electrodes, respectively. The electrons and the holes recombine in the organic light emitting layer to generate excitons. Light is emitted from the organic light-emitting device when the excitons transition from an excited state to the ground state.
Implementation Method 2
In the case that an organic light emitting layer of an organic light-emitting device is made of a phosphorescent material, triplet excitons contribute to emission, and thus the organic light-emitting device exhibits higher luminous efficiency
Data Source
AI summary
Discussed herein is an organic light-emitting device capable of increasing luminous efficiency and panel efficiency while improving color gamut. The organic light-emitting device includes a red organic light emitting layer including a single host material of hole transport type and a yellow-green organic light emitting layer including a plurality of host materials in a light-emitting stack. Instead of using an additional host material for the organic light emitting layers, the material of the electron transport layer and the material of the hole transport layer is used as the host material of the yellow-green organic light emitting layer, and the material of the hole transport layer is used as the host material of the red organic light emitting layer. Accordingly, the number of materials of the organic light emitting layers is reduced, such that the fabricating process becomes simpler.