OLED Anode with Al-Ni-ZnO Stack and Cyano Layer
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Solution Overview
Problem
Existing organic light-emitting devices (OLEDs) face challenges in achieving excellent driving voltage characteristics and power efficiency due to issues like galvanic corrosion between different metal electrodes, leading to inconsistent luminance and reduced image quality.
Innovation Solution
The OLED design includes a substrate with a first electrode featuring a sequentially stacked Al-based reflective layer containing nickel and a transparent conductive layer, along with a second element-containing zinc oxide layer, and an organic layer containing a cyano group-containing compound, which helps in stabilizing the contact resistance and enhancing hole injection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional electrode structure with multiple metal layers is used, then hole injection efficiency may be improved, but galvanic corrosion occurs between different metal electrodes leading to increased contact resistance and reduced reliability
Solution Approach 1:
The patent introduces a zinc oxide layer as an intermediary between the aluminum-based reflective layer and the organic emission layer. This zinc oxide layer acts as a mediator that prevents direct contact between dissimilar metals, thereby eliminating galvanic corrosion while maintaining effective hole injection into the organic layer.
Solution Approach 2:
The electrode structure employs composite materials by combining aluminum-based reflective layer with nickel and zinc oxide in a specific stacked configuration. This composite structure leverages the high reflectivity of aluminum, the corrosion resistance of zinc oxide, and the conductivity of nickel to achieve both reliable electrical contact and protection against galvanic corrosion.
2Reliability
If the Al-based reflective layer contains nickel and zinc oxide, then galvanic corrosion is reduced and contact resistance is stabilized, but device structure complexity increases
Solution Approach 1:
The electrode is segmented into distinct functional layers: an aluminum-based reflective layer for light reflection, a nickel-containing layer for electrical conductivity, and a zinc oxide layer for corrosion protection and hole injection. This segmentation allows each layer to perform its specific function optimally while maintaining overall structural organization.
Solution Approach 2:
The aluminum-based reflective layer serves multiple functions simultaneously: it provides high light reflectivity, acts as a hole injection electrode, and when combined with nickel and zinc oxide, provides corrosion resistance. This multi-functionality reduces the need for separate dedicated layers for each function.
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 results in OLEDs with improved driving voltage characteristics and power efficiency, reducing galvanic corrosion and maintaining high reflectivity and thermal stability, thereby enhancing image quality and luminescent efficiency.
Implementation Method 1
the Al-based reflective layer including a first element and nickel (Ni)... maintaining high reflectivity
Implementation Method 2
a first layer including a cyano group-containing compound, the first layer being between the first electrode and the emission layer... enhancing hole injection efficiency
Implementation Method 3
The first electrode further includes a second element-containing zinc oxide layer, the second element including at least one of aluminum (Al), indium (In), gallium (Ga), germanium (Ge), gadolinium (Gd), zirconium (Zr), molybdenum (Mo), and nickel (Ni)
Implementation Method 4
reducing galvanic corrosion... the Al-based reflective layer including a first element and nickel (Ni)... a second element-containing zinc oxide layer
Data Source
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AI summary
The present invention refers to an organic light-emitting device including a substrate; a first electrode on the substrate; a second electrode; an organic layer between the first electrode and the second electrode, the organic layer including an emission layer; and a first layer including a cyano group-containing compound, the first layer being between the first electrode and the emission layer, wherein the first electrode includes an Al-based reflective layer and a transparent conductive layer sequentially stacked on the substrate, the Al-based reflective layer including a first element and nickel (Ni), and the first element includes at least one of lanthanum (La), cerium (Ce), praseodymium (Pr), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).