OLED Electron Injection Layer Composite Oxide Metal
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Solution Overview
Problem
Conventional liquid crystal displays have limitations in response speed and viewing angle due to the need for a separate backlight, and organic light emitting diodes (OLEDs) aim to address these issues by providing a self-emitting solution with improved efficiency and lifespan.
Innovation Solution
The OLEDs include a first and second electrode with an emission layer in between, an electron injection layer comprising an oxide with a relative dielectric constant of 10 or more and a metal with a work function of 4.0 eV or less, along with an electron transport layer and a hole transport layer, enhancing electron injection and light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional electron injection layer is used in OLEDs, then the device structure is simple, but the electron injection efficiency and device lifespan are insufficient
Solution Approach 1:
The electron injection layer is constructed as a composite structure comprising a first electron injection layer and a second electron injection layer with different material compositions and functions. The first layer (closer to emission layer) contains materials optimized for electron injection into the emission layer, while the second layer (closer to electrode) contains materials optimized for electron injection from the electrode, creating a synergistic effect that improves overall electron injection efficiency and device lifespan without excessive complexity
Solution Approach 2:
The electron injection layer is divided into multiple distinct layers (first electron injection layer and second electron injection layer) with different thicknesses, material compositions, and functional optimizations. This segmentation allows each layer to perform its specific function optimally, with the first layer focusing on electron injection into the emission layer and the second layer focusing on electron injection from the electrode, thereby resolving the contradiction between improved reliability and device complexity
2Productivity
If a single-layer electron injection layer is used, then the manufacturing process is simple, but the electron injection efficiency and luminance are limited
Solution Approach 1:
The electron injection layer employs composite material composition where the first electron injection layer contains specific organic compounds optimized for electron injection into the emission layer, and the second electron injection layer contains different organic compounds optimized for electron injection from the electrode. This composite approach enhances electron injection efficiency and luminance output while maintaining reasonable manufacturing complexity through systematic material selection
Solution Approach 2:
Different regions of the electron injection layer (first layer vs. second layer) are assigned different material qualities and compositions tailored to their specific functional requirements. The first layer uses materials with properties optimized for interfacing with the emission layer, while the second layer uses materials optimized for interfacing with the electrode, achieving local optimization that improves overall electron injection efficiency and luminance without requiring complete redesign of the entire 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
This configuration improves the lifespan and efficiency of the OLEDs, particularly for blue light emission, with the electron injection layer formed by co-depositing materials like Yb and WO3, resulting in enhanced luminance and extended life span compared to single-layer configurations.
Implementation Method 1
an electron injection layer between the second electrode and the emission layer, the electron injection layer including an oxide having a relative dielectric constant of 10 or more and a metal having a work function of 4.0 eV or less
Implementation Method 2
an emission layer between the first electrode and the second electrode
Data Source
AI summary
An organic light emitting element, includes a first electrode and a second electrode facing each other; an emission layer between the first electrode and the second electrode; and an electron injection layer between the second electrode and the emission layer, the electron injection layer including an oxide having a relative dielectric constant of 10 or more and a metal having a work function of 4.0 eV or less.