OLED Amorphous Oxide Layer Gas Barrier
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Solution Overview
Problem
Conventional organic light emitting diode displays face issues with silver in the reflective metal layer binding to external gases, leading to potential short-circuiting due to grain boundaries in the transparent conductive layer, which affects the reliability and efficiency of light emission.
Innovation Solution
Incorporating an amorphous oxide layer with a lower work function than the upper transparent conductive layer, made of materials like silver, copper, or aluminum, to prevent gas permeation and minimize light loss, while ensuring hole injection efficiency into the organic emission layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transparent conductive layer with grain boundaries is used, then light transmission is achieved, but gas permeation occurs leading to short-circuiting
Solution Approach 1:
An amorphous oxide layer is introduced as an intermediary barrier between the reflective metal layer and the transparent conductive layer. This intermediate layer prevents gas permeation through the grain boundaries of the transparent conductive layer, thereby eliminating the short-circuiting issue while maintaining light transmission properties.
Solution Approach 2:
The patent employs a composite structure consisting of multiple layers with different properties: a reflective metal layer, an amorphous oxide layer, and a transparent conductive layer. This composite material approach combines the light-reflecting capability of metal with the gas-barrier properties of amorphous oxide and the transparency of the conductive layer, resolving the contradiction between light transmission and gas permeation resistance.
2Use of energy by moving object
If silver is used in the reflective metal layer, then light reflection efficiency is improved, but binding to external gases causes short-circuiting
Solution Approach 1:
The amorphous oxide layer serves as a protective intermediary between the silver-containing reflective metal layer and external gases. This barrier prevents gas molecules from reaching and binding to the silver, thereby maintaining both the light reflection efficiency of the silver and the reliability of the device by preventing short-circuiting.
Solution Approach 2:
The patent converts the potential harm of gas binding to silver into a benefit by introducing the amorphous oxide layer. This layer specifically targets and prevents the harmful gas-silver interaction, allowing the silver to maintain its excellent light reflection properties without suffering from gas-induced degradation or short-circuiting.
3Object-affected harmful factors
If an amorphous oxide layer is added, then gas permeation is prevented, but device complexity increases
Solution Approach 1:
The amorphous oxide layer is applied locally at the critical interface between the reflective metal layer and the transparent conductive layer, where gas permeation through grain boundaries occurs. This localized approach provides gas protection precisely where needed without unnecessarily complicating other parts of the device structure.
Solution Approach 2:
The patent changes the structural parameter of the transparent conductive layer by introducing an amorphous oxide layer with different physical and chemical properties. This parameter change (adding a layer with amorphous structure instead of crystalline) provides gas barrier functionality while maintaining compatibility with existing manufacturing processes, thus limiting the increase in device complexity.
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 enhances the reliability and display quality of the organic light emitting diode by preventing gas penetration and maintaining efficient light transmission, reducing the risk of short-circuiting and improving hole injection into the organic emission layer.
Implementation Method 1
the upper transparent conductive layer is amorphous... the amorphous oxide layer... to prevent gas permeation
Implementation Method 2
a first electrode including a reflective metal layer formed of a light-reflective metal... emitting light in a direction of the second electrode
Implementation Method 3
The amorphous oxide layer may have a lower work function than the upper transparent conductive layer... improving hole injection into the organic emission layer
Data Source
AI summary
An organic light emitting diode includes a first electrode including a first electrode including a reflective metal layer formed of a light-reflective metal, an upper transparent conductive layer positioned on the reflective metal layer, and a protective layer positioned on the upper transparent conductive layer; an organic emission layer positioned on the first electrode; and a second electrode positioned on the organic emission layer, wherein the upper transparent conductive layer is amorphous.