Transparent Electrode Using Silver and Lanthanoid Affinity Layer
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Solution Overview
Problem
Existing transparent electrodes for organic electroluminescence devices face challenges in achieving both conductivity and light-transmitting properties while maintaining durability, particularly due to issues with silver migration and the use of rare metals like indium and the limitations of sputtering methods.
Innovation Solution
A transparent electrode comprising a conductive silver layer adjacent to a metal affinity layer containing an organic compound with a lanthanoid, such as samarium, europium, or ytterbium, which suppresses silver aggregation and enhances conductivity and durability by interacting with silver atoms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sputtering method is used to form the transparent electrode, then conductivity is improved, but the organic layer is damaged and durability deteriorates
Solution Approach 1:
The patent introduces an electron injection layer as an intermediary between the organic light-emitting layer and the silver conductive layer. This electron injection layer acts as a buffer that prevents direct contact between the sputtering process and the organic layer, thereby protecting the organic material from damage while still allowing effective electron injection and maintaining conductivity.
2Reliability
If the thickness of silver film is increased to suppress migration, then conductivity is maintained, but light-transmitting property is reduced
Solution Approach 1:
The electron injection layer serves as a mediator that enables effective electron injection into the silver film, allowing the use of thinner silver layers that maintain conductivity while preserving light-transmitting properties. The intermediary layer facilitates electron transport without requiring thick metal deposits.
Solution Approach 2:
The patent creates a composite structure combining the electron injection layer with the silver conductive layer. This composite material approach allows the system to achieve both electrical conductivity and optical transparency by combining materials with complementary properties rather than relying on thick silver alone.
3Illumination intensity
If ITO is used as the transparent electrode material, then light-transmitting property is achieved, but material cost increases due to rare metal indium
Solution Approach 1:
The patent replaces expensive rare metal ITO with a cost-effective combination of abundant materials: an organic electron injection layer and a silver-based conductive layer. This substitution uses readily available materials that are significantly cheaper than indium tin oxide, while maintaining the required optical and electrical properties through the composite structure.
4Object-affected harmful factors
If vapor deposition method is used to form transparent electrode, then organic layer is protected, but silver migration occurs and conductivity reduces
Solution Approach 1:
The electron injection layer acts as a protective intermediary between the substrate and the silver film during vapor deposition. This intermediary layer prevents direct interaction that would cause silver migration, while still enabling effective electron injection to maintain conductivity. The buffer layer stabilizes the silver film structure.
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 provides a transparent electrode with improved conductivity, light-transmitting properties, and durability, enabling effective electron injection and carrier transport in organic electroluminescence devices without the need for rare metals or high-temperature annealing.
Implementation Method 1
a metal affinity layer adjacent to the conductive layer, wherein the conductive layer is composed of silver as a main component, the metal affinity layer contains an organic compound and a lanthanoid
Implementation Method 2
attempts have been made to form the transparent electrode by forming a thin film of a metal material by a vapor deposition method
Data Source
AI summary
A transparent electrode includes a conductive layer and at least one metal affinity layer adjacent to the conductive layer. The conductive layer is composed of silver as a main component. The metal affinity layer contains an organic compound and a lanthanoid. The organic compound is a compound including a heteroatom having an unshared electron pair in a molecule.