Multilayer Barrier Substrate for Organic Electronic Devices
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Solution Overview
Problem
In organic electronic devices (OEDs), the combination of organic and inorganic material layers often leads to interlayer delamination due to stress, resulting in reduced durability and inadequate water vapor transmission rates, particularly with plastic substrates that are vulnerable to water and oxygen permeation.
Innovation Solution
A substrate comprising a flexible base film with a multilayer inorganic material layer and an elastic layer, where the elastic layer is formed on, under, or within the inorganic material layer to mitigate stress, and the inorganic material layer is structured to inhibit crystallization and enhance barrier properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single inorganic barrier layer is formed on a plastic substrate to prevent water and oxygen permeation, then the barrier function is improved, but adhesive strength decreases due to partial crystallization of the barrier layer
Solution Approach 1:
The inorganic barrier layer is divided into multiple thin sub-layers (first inorganic sub-layer, second inorganic sub-layer, etc.) with each layer having a thickness of 1 nm to 10 nm. This segmentation prevents partial crystallization that occurs in single thick layers, thereby maintaining adhesive strength while preserving the barrier function against water and oxygen permeation.
Solution Approach 2:
The patent employs composite material structures by alternating inorganic barrier layers with organic adhesive layers (first organic layer, second organic layer). This composite structure combines the barrier properties of inorganic materials with the adhesive properties of organic materials, solving both the barrier function and adhesive strength requirements simultaneously.
2Strength
If a multilayer structure of inorganic barrier layers and organic layers is used to improve adhesive strength, then adhesive strength is improved, but water vapor transmission rate increases due to permeation of water
Solution Approach 1:
Different regions of the barrier structure are assigned different functions: inorganic sub-layers provide water and oxygen barrier properties, while organic layers provide adhesive strength. The inorganic layers are specifically designed with thin thickness (1-10 nm) to maintain barrier function while the organic layers compensate for adhesive requirements, achieving local optimization of both properties.
Solution Approach 2:
The patent transitions from a single-dimensional barrier approach to a multi-dimensional layered structure. By creating alternating inorganic and organic layers in the vertical dimension, the system achieves barrier function in one dimension while addressing adhesive requirements in another dimension, effectively solving the water vapor transmission problem.
3Reliability
If an inorganic barrier layer is formed to satisfy WVTR requirements, then barrier function is improved, but stress from the inorganic layer causes film separation or cracks in the transparent electrode layer
Solution Approach 1:
Organic adhesive layers are placed between the inorganic barrier layers and the transparent electrode layer to provide cushioning against stress. These organic layers act as buffer zones that absorb and distribute the stress generated by the inorganic layers, preventing film separation and cracks in the transparent electrode while maintaining the barrier function.
4Reliability
If the inorganic material layer is made thicker to improve barrier properties, then water vapor transmission rate is improved, but crystallization increases causing adhesive strength to decrease
Solution Approach 1:
Instead of using a single thick inorganic layer that would crystallize and lose adhesive strength, the patent segments the barrier function into multiple thin inorganic sub-layers (each 1-10 nm thick). This segmentation maintains the cumulative barrier effect against water vapor while preventing crystallization in each individual layer, thereby preserving adhesive strength.
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 prevents interlayer delamination, enhances durability, and improves light extraction efficiency while maintaining the required physical properties of the OED, specifically by using a flexible base film with a multilayer inorganic structure and an elastic layer to manage stress and crystallization.
Implementation Method 1
an elastic layer, which has an elastic modulus of 20 to 400 GPa at 23°C. Here, the inorganic material layer is formed on the base film. In this case, the elastic layer is formed on or under the inorganic material layer, or in the inorganic material layer.
Implementation Method 2
the plastic substrate is vulnerable to permeation of water and oxygen. Particularly, when a display device including an OLED using the plastic substrate is manufactured, the water and oxygen are permeated from the substrate, resulting in reducing a lifespan of the OLED.
Data Source
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AI summary
Provided are a substrate for an organic electronic device (OED) and a use thereof. Provided is a substrate for a device having excellent durability by preventing interlayer delamination occurring due to internal stress in a structure in which an organic material and an inorganic material are mixed. In addition, provided is an OED having another required physical property such as excellent light extraction efficiency using the substrate, as well as the excellent durability.