Auxiliary Electrode Laminate for OLED Light Extraction
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Solution Overview
Problem
Existing transparent electrodes in organic light emitting devices have high electrical resistance and low light extraction efficiency, particularly in large-area devices, which hinders commercialization and light emission efficiency.
Innovation Solution
An electrode laminate with a laminated auxiliary electrode structure, comprising a first layer with reflectivity of 80% or greater at 550 nm and a second layer with a higher etching rate, is integrated between the first electrode and the substrate, or provided on the side surface of the first electrode, to reduce electrical resistance and enhance light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If transparent conductive films such as ITO and ZnO are used as electrodes, then transparency is achieved, but electrical resistance becomes excessively high
Solution Approach 1:
The patent employs a composite electrode structure combining transparent conductive oxide (TCO) layers with metal layers (such as Al, Mo, or their alloys). The TCO layer provides transparency while the metal layer provides low electrical resistance, creating a composite material system that achieves both optical transparency and electrical conductivity required for large-area illumination devices
2Area of stationary object
If large-area illumination devices are formed, then device size increases, but electrical resistance increases significantly
Solution Approach 1:
The composite electrode structure with metal layers embedded in or adjacent to TCO layers maintains low electrical resistance even when scaled to large areas. The metal pathways provide conductive routes that prevent resistance increase with device area expansion
Solution Approach 2:
The patent introduces auxiliary electrode layers with specific reflective properties at strategic locations (between the first electrode and substrate, or adjoining the substrate) to locally enhance light extraction efficiency and maintain electrical performance across the entire large-area device
3Use of energy by moving object
If light is produced in the organic light emitting device, then light emission occurs, but 30% of light is locked inside the device due to total reflection
Solution Approach 1:
The auxiliary electrode layer is strategically positioned between the first electrode and substrate or adjoining the substrate to create localized optical interference effects. This layer has specific optical properties (reflectivity of 80% or greater at 550 nm) that locally enhance light extraction at critical interfaces where total reflection occurs
Solution Approach 2:
The auxiliary electrode layer acts as an intermediary between the organic light emitting layer and the substrate/air interface. It mediates the optical interaction by providing controlled reflection and interference effects that prevent total internal reflection, thereby extracting trapped light without directly contacting the organic layer
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 reduces electrical resistance and improves light extraction efficiency by reflecting light at the interface between the auxiliary electrode and the substrate, preventing total reflection and enhancing light emission from the organic material layer.
Implementation Method 1
the auxiliary electrode of the first electrode has a laminated structure of a first layer having reflectivity of 80% or greater at a wavelength of 550 nm
Data Source
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AI summary
The present specification provides an electrode laminate including a substrate, an electrode provided on the substrate, and an auxiliary electrode electrically connecting to the electrode and has a laminated structure of a first layer having reflectivity of 80% or greater at a wavelength of 550 nm and a second layer having a higher etching rate compared to the first layer, wherein the auxiliary electrode is either provided between the electrode and the substrate, or provided so that the first layer of the auxiliary electrode adjoins at least part of the side surface of the electrode, and an organic light emitting device including the electrode laminate.