Amorphous Carbon Multilayer Electrode for OLED Radiation Extraction
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Solution Overview
Problem
Existing organic light-emitting diode (OLED) structures face complications in fabrication due to the need for additional electrode deposition and risk of impairing encapsulation functions, particularly with silicon-containing materials that pose hazards and have limited conductivity compared to amorphous carbon-based solutions.
Innovation Solution
The use of amorphous carbon multilayers for both electrodes, with refractive index differences achieved through varying deposition conditions rather than silane content, providing conductivity, encapsulation, and a Bragg mirror effect without silicon, allowing safer fabrication and improved radiation extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If silicon-containing materials are used to create refractive index differences in the encapsulating multilayer, then the optical characteristics are optimized, but the fabrication process becomes hazardous and the conductivity is limited
Solution Approach 1:
The patent changes the material composition parameter from silicon-containing materials to amorphous carbon-based materials. This substitution eliminates fabrication hazards associated with silane while maintaining the ability to create refractive index differences through deposition condition variations, thus resolving the contradiction between optimized optical characteristics and safe fabrication
Solution Approach 2:
The patent applies local quality by creating sublayers with different refractive indices within the amorphous carbon multilayer structure. By varying deposition conditions locally to produce regions with different optical properties, the patent achieves the necessary optical characteristics without requiring hazardous silicon-containing materials
2Reliability
If an encapsulating multimirror layer is positioned in the lower position, then the encapsulation function is improved, but the fabrication process becomes more complicated requiring contact holes or vias
Solution Approach 1:
The patent applies multi-functionality by designing the lower electrode as a multilayer structure that simultaneously provides electrical conduction and optical reflection functions. This eliminates the need for separate encapsulating multimirror layer with contact holes, thereby maintaining reliable encapsulation while simplifying the fabrication process
Solution Approach 2:
The patent merges the electrode function and the encapsulating mirror function into a single multilayer structure. By combining these two functions into one component, the patent eliminates the need for additional contact holes or vias through the encapsulating layer, thus reducing fabrication complexity while maintaining encapsulation reliability
3Illumination intensity
If materials of different refractive indices are used in the encapsulating multilayer, then the Bragg mirror effect is enhanced, but the electrical conductivity is reduced due to insulating materials
Solution Approach 1:
The patent changes the material parameter from insulating materials to amorphous carbon-based materials that can provide both optical contrast and electrical conductivity. By maintaining the ability to create refractive index differences while using conductive materials, the patent resolves the contradiction between enhanced Bragg mirror effect and electrical conductivity
Solution Approach 2:
The patent uses composite amorphous carbon structures with varying deposition conditions to create sublayers that exhibit both optical contrast (different refractive indices) and electrical conductivity. This composite approach allows simultaneous achievement of enhanced Bragg mirror effect and maintained conductivity
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 simplifies the fabrication process, enhances radiation extraction, and maintains effective encapsulation without the hazards associated with silicon-containing materials, while ensuring high conductivity and optimized optical performance.
Implementation Method 1
The different refractive indices are obtained from the different deposition conditions and allow extraction of the radiation emitted by the organic electroluminescent layer
Implementation Method 2
acts as a diffusion barrier to certain elements from the substrate into the organic electroluminescent layer
Data Source
Figure 1
AI summary
Diode comprising a substrate (1) and an organic electroluminescent layer (3) interposed between a lower electrode and an upper electrode (4), at least one of which electrodes is formed from a multilayer (2) which is itself formed by the stack of adjacent sublayers (21, 22) made of amorphous carbon, having different refractive indices n1, n2. The amorphous carbon contains no added silicon, thereby making it possible to avoid using silane for the manufacture. The multilayer provides an electrode function, a multimirror function and an encapsulation function.