OLED Light-Emitting Layer Oligomer Polymer Composite
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Solution Overview
Problem
Organic light-emitting devices produced by coating processes have limited lifetime due to difficulties in molecular weight control and purification of polymer compounds, as well as issues with space charge layers at interfaces, leading to degradation.
Innovation Solution
Incorporating an oligomer material with a molecular weight of 1,000 to 10,000, which is highly pure and has a high degree of freedom in material design, along with a n-conjugated polymer material to improve carrier injectability and prevent crystallization, while also using a triplet light-emitting material for enhanced efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a polymer compound is used as a light-emitting body material, then the device can be produced by coating process at low cost, but the molecular weight control and purification become difficult leading to limited device lifetime
Solution Approach 1:
The patent uses a composite material system combining oligomer (1,000-10,000 molecular weight) and polymer compounds in the light-emitting layer. The oligomer component provides easy purification and molecular weight control while maintaining coating processability, and the polymer component ensures film formation stability and prevents crystallization, together resolving the contradiction between manufacturing ease and device lifetime
Solution Approach 2:
The patent changes the molecular weight parameter of the light-emitting body material from typical polymer ranges to a specific oligomer range (1,000-10,000). This parameter change enables both easy purification and good coating performance while preventing crystallization, thereby improving device lifetime without sacrificing manufacturing ease
2Manufacturing precision
If a low-molecular-weight compound is used, then the purification becomes easier, but the crystallization tendency increases reducing device stability
Solution Approach 1:
The patent optimizes the molecular weight parameter to a specific range (1,000-10,000) for oligomers, which is higher than typical low-molecular compounds. This parameter change reduces crystallization tendency while maintaining easy purification capability, resolving the contradiction between purification ease and compositional stability
3Manufacturing precision
If only oligomer material is used in the light-emitting layer, then the purity and coating performance improve, but the material design freedom is reduced
Solution Approach 1:
The patent creates a composite light-emitting layer containing both oligomer and polymer materials. This composite approach combines the high purity and excellent coating performance of oligomers with the design flexibility and crystallization resistance of polymers, thereby maintaining coating performance while enhancing material design freedom
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 combination of oligomer and polymer materials in the light-emitting layer results in a device with improved emission efficiency, extended lifetime, and reduced crystallization, enabling a stable and efficient organic light-emitting device that can be produced at low cost through a coating process.
Implementation Method 1
The light-emitting layer includes an oligomer material and a polymer material
Data Source
AI summary
Provided is an organic light-emitting device having a high emission efficiency and a long lifetime. The organic light-emitting device (10) includes an anode (2), a cathode (6), and a stack body including at least a light-emitting layer (4) and interposed between the anode (2) and the cathode (6), in which the light-emitting layer (4) includes an oligomer material and a polymer material.