Trivalent Metal Passivation Layer for Moisture-Resistant OLEDs
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Solution Overview
Problem
Existing absorbents for optical elements, such as organic light-emitting devices, are ineffective in preventing moisture and oxygen infiltration, leading to degradation and reduced emission properties, especially in top emission type displays and flexible displays, where they can block light and are difficult to uniformly disperse without compromising light transparency.
Innovation Solution
A passivation layer comprising compounds represented by Formulas 1 and 2, which are trivalent metal-based and combined with a thermoplastic resin, providing high light transmittance and moisture absorption capabilities, allowing for the formation of an absorbent that captures moisture without affecting light emission and can be applied to both bottom and top emission type displays, including flexible displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alkali earth metal oxides (BaO, CaO) are used as absorbent, then water absorption capability is improved, but light transmittance deteriorates and device thickness increases
Solution Approach 1:
The patent changes the chemical composition parameters by using trivalent metal compounds (Al, Ga, In) with specific organic groups instead of traditional alkali earth metal oxides. This parameter change enables both high water absorption capability and high light transmittance (>80% at 550nm) simultaneously, resolving the contradiction between moisture protection and light transmission in top-emission OLEDs.
Solution Approach 2:
The patent creates composite materials by combining trivalent metal compounds with organic groups (alkyl, aryl, cycloalkyl) to form new compounds that exhibit both excellent moisture absorption properties and optical transparency. These composite structures achieve the dual functionality of protecting against moisture while maintaining light emission in top-emission displays.
2Reliability
If inorganic compound particles are used as absorbent, then water absorption capability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent changes the physical state parameter from particulate inorganic compounds to organic-soluble trivalent metal compounds. This enables the absorbent to be dissolved in solvents and applied as uniform coatings through simple solution processing, eliminating the need for complex particle dispersion and concave member structures, thereby reducing device complexity while maintaining water absorption capability.
3Illumination intensity
If transparent polymer absorbents are used, then light transmittance is improved, but water absorption capability deteriorates
Solution Approach 1:
The patent develops composite materials that integrate the transparency of organic polymers with the high water absorption capability of trivalent metal compounds. The resulting compounds maintain the optical clarity needed for top-emission displays while achieving superior moisture absorption performance, overcoming the limitations of conventional transparent polymers.
Solution Approach 2:
The patent changes the chemical functional groups and molecular structure parameters to create compounds with both high optical transparency and high affinity for water molecules. By selecting appropriate organic groups (alkyl, aryl, cycloalkyl) attached to trivalent metal centers, the material achieves simultaneous optimization of light transmittance and water absorption capability.
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 effectively prevents moisture infiltration, maintains emission properties over extended use, and ensures high light transmittance, enabling the use in dual emission type OLEDs and other optical elements like semiconductors and solar cells, while preventing physical impact and maintaining flexibility.
Implementation Method 1
alkali earth metal oxides such as barium oxide (BaO) or calcium oxide (CaO) continues because they are able to specifically capture water molecules using a chemical reaction
Implementation Method 2
moisture or oxygen in the atmosphere infiltrates the light-emitting device and thus the electrode may be oxidized
Data Source
AI summary
This invention relates to an absorbent and a passivaton layer for an optical element including the same, which may suppress infiltration of moisture without blocking light, may be applied to flexible substrates and may prevent deterioration of optical elements thus maintaining emission properties during extended use.