OLED Connecting Layer Material Matching for Carrier Balancing
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Solution Overview
Problem
Existing OLEDs face challenges in balancing carriers during light emission due to the presence of a connecting layer, leading to reduced light efficiency and unexpected emission of undesired colors, as the layer's thickness affects the interface between layers formed by different processes.
Innovation Solution
An OLED structure with a connecting layer of specific material and thickness, corresponding to the carriers in the first carrier transport layer, is sequentially stacked with a second portion using different processes, including vacuum evaporation and solution methods, to improve light emitting efficiency and prevent unexpected emission of light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a connecting layer is formed between the light emitting layer and the carrier transport layer, then the interface properties between layers formed by different processes are improved, but carrier balancing during light emission deteriorates
Solution Approach 1:
The patent changes the material parameters of the connecting layer by selecting materials with specific HOMO and LUMO energy levels that match the adjacent layers. This parameter optimization allows the connecting layer to improve interface properties while maintaining proper carrier transport and balancing, thereby resolving the contradiction between interface quality and carrier balancing.
Solution Approach 2:
The patent applies local quality by giving the connecting layer specific localized functions: it provides good interface adhesion and energy level matching while maintaining transparency to carrier transport. The layer is designed with thickness and material composition optimized for its specific position between the light emitting layer and carrier transport layer, allowing it to improve interface properties without disrupting overall carrier balancing.
2Object-generated harmful factors
If the connecting layer is made too thin, then carrier quenching is reduced, but light emitting efficiency is reduced
Solution Approach 1:
The patent optimizes the thickness parameter of the connecting layer to a specific range that balances two opposing effects: thin enough to minimize carrier quenching but thick enough to provide sufficient energy level matching and interface stability. This parameter optimization resolves the contradiction between reducing carrier quenching and maintaining light emitting efficiency.
3Reliability
If the connecting layer is made too thick, then interface properties are improved, but unexpected emission of light occurs
Solution Approach 1:
The patent constrains the thickness parameter of the connecting layer within a specific range to prevent it from becoming too thick. This thickness control prevents the formation of defects and unintended emission centers that would cause unexpected light emission, while still maintaining sufficient interface properties through optimized material selection and thickness within the specified range.
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 solution stabilizes light emission, maintains good efficiency, and ensures ideal color output by positioning the carrier recombination region close to the electrode, reducing defects and the influence of connecting layer thickness on emitted light color.
Implementation Method 1
a cathode layer, an electron injection layer, an electron transport layer and a light emitting layer may be formed using a vacuum evaporation method
Implementation Method 2
a hole transport layer and a hole injection layer may be formed using a solution method
Data Source
AI summary
The present disclosure provides an organic light emitting diode (OLED) and a manufacturing method of the same, and a display device. The OLED comprises a first portion and a second portion which are manufactured by different processes and sequentially stacked, wherein the first portion comprises a first carrier transport layer, a first light emitting layer, and a connecting layer between the first light emitting layer and the second portion, which are sequentially stacked, the second portion comprises a second carrier transport layer, the first light emitting layer comprises an N-type base material and a P-type base material, and the connecting layer comprises a material corresponding to carriers in the first carrier transport layer. The OLED provided by the present disclosure can not only make light emission stable, maintain a good efficiency of light emission, but obtain light with an ideal color and prevent a phenomenon of “unexpected emission of light”.