Transparent Electrode with Light Scattering Particles for OLEDs
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Solution Overview
Problem
Existing organic electroluminescent elements face challenges in achieving high light extraction efficiency due to the use of small conductive nanoparticles and neglect of refractive index in scattering layers, leading to increased costs and complexity in the light extraction process.
Innovation Solution
An organic electroluminescent element is designed with a transparent electrode containing light scattering particles of at least 0.5 μm in size and a refractive index equal to or higher than the organic light-emitting layer, eliminating the need for a separate light extraction layer and simplifying the film formation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate light extraction layer is added to improve light extraction efficiency, then light extraction efficiency is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the light extraction function with the transparent electrode by incorporating light scattering particles into the electrode structure. This merging eliminates the need for a separate light extraction layer, thereby improving light extraction efficiency while reducing device complexity and manufacturing cost.
Solution Approach 2:
The transparent electrode is designed to perform multiple functions simultaneously: it provides electrical conductivity, maintains transparency, and enables light extraction through integrated light scattering particles. This multi-functionality resolves the contradiction by eliminating the need for additional dedicated light extraction layers.
2Reliability
If multiple layers are used to achieve both conductivity and light scattering, then light extraction efficiency is improved, but manufacturing process complexity increases
Solution Approach 1:
The patent merges the light scattering function into the transparent electrode layer itself, allowing both conductivity and light scattering to be achieved in a single integrated structure. This eliminates the need for multiple separate layers and simplifies the manufacturing process while maintaining high light extraction efficiency.
Solution Approach 2:
The transparent electrode is formed as a composite material containing conductive components and light scattering particles within the same layer. This composite structure enables simultaneous achievement of electrical conductivity and light scattering functionality in a single manufacturable layer.
3Ease of manufacture
If conventional scattering layers are used without considering refractive index, then manufacturing is simpler, but light extraction efficiency cannot be improved
Solution Approach 1:
The patent optimizes the refractive index parameter of the transparent electrode containing light scattering particles to enhance light extraction efficiency. By carefully selecting materials and adjusting the refractive index within a specific range, the invention achieves high light extraction efficiency while maintaining manufacturing simplicity through a single integrated layer.
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 significantly improves light extraction efficiency while reducing costs and process complexity by integrating light scattering functionality into the transparent electrode.
Implementation Method 1
contains at least one type of light scattering particles that are transparent and have a primary particle size of at least 0.5 μm
Implementation Method 2
which is composed of the light scattering particles and a component having a refractive index equal to or higher than the refractive index of the organic light-emitting layer
Data Source
AI summary
It is an object of the present invention to provide an organic electroluminescent element with which no light extraction layer needs to be produced separately, which has a transparent electrode that is advantageous in terms of cost and can be formed by a simple film formation process, and which is excellent from the standpoint of light extraction efficiency. The present invention provides an organic electroluminescent element in which a substrate, a first electrode adjacent to this substrate, an organic layer including at least one organic light-emitting layer, and a second electrode adjacent to this organic layer are formed in this order, with this organic electroluminescent element being such that at least one of the aforementioned electrodes is a transparent electrode which is transparent, which contains at least one type of light scattering particles that are transparent and that have a primary particle size of at least 0.5 μm, and which is composed of the aforementioned light scattering particles and a component having a refractive index equal to or higher than the refractive index of the aforementioned organic light-emitting layer.