Organic Light Emitting Device With Resonant Hole Injection Layer
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Solution Overview
Problem
Conventional organic light emitting devices do not meet desired levels of driving voltage, current density, brightness, color purity, efficiency, and lifetime.
Innovation Solution
An organic light emitting device with a substrate, a pair of electrodes, and an organic layer including a hole injection layer of specific thickness ranges under red, green, and blue emission regions, utilizing phenylcarbazole-based compounds to enhance resonance and stability, resulting in improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional organic light emitting device structure is used, then the device can be manufactured with standard processes, but the driving voltage, current density, brightness, color purity, efficiency and lifetime do not meet desired levels
Solution Approach 1:
The organic layer is segmented into multiple functional sub-layers: hole injection layer (1600-2200 Å), hole transport layer (200-400 Å), emission layer (300-500 Å), electron transport layer (200-400 Å), and electron injection layer (100-300 Å). Each layer is optimized for its specific function, allowing independent optimization of device performance parameters including lifetime, while maintaining a systematic approach to device architecture.
Solution Approach 2:
Different thicknesses and materials are used for different layers to optimize local functions: the hole injection layer uses thicker configuration (1600-2200 Å) for improved hole injection and resonance, while the electron injection layer uses thinner configuration (100-300 Å) for electron injection efficiency. The emission layer thickness (300-500 Å) is optimized for light emission and color purity, demonstrating local quality optimization throughout the device structure.
2Duration of action of stationary object
If the hole injection layer thickness is increased to improve resonance and lifetime, then the lifetime and luminance are enhanced, but the driving voltage and layer complexity increase
Solution Approach 1:
The hole injection layer thickness is optimized to a specific range of 1600-2200 Å, which represents a parameter change from conventional thinner layers. This thickness optimization creates resonance conditions that enhance device lifetime and luminance while maintaining acceptable driving voltage levels. The specific thickness range is determined through systematic parameter optimization to achieve the desired balance between lifetime enhancement and electrical performance.
3Productivity
If multiple functional layers are added to improve efficiency and lower driving voltage, then the efficiency improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
Each organic layer is designed with multi-functionality: the hole transport layer not only transports holes but also provides structural support and interfaces with the emission layer; the electron transport layer performs electron transport while maintaining device stability; the emission layer generates light while defining device color characteristics. This multi-functionality approach allows efficient device operation with a moderate number of layers rather than requiring excessive specialized 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
The device achieves low driving voltage, excellent current density, high brightness, excellent color purity, high efficiency, and long lifetime, particularly with enhanced stability and luminance.
Implementation Method 1
an organic light emitting device including a hole injection layer having a predetermined range of thickness between a pair of electrodes capable of generating resonance during the operation of the light emitting device
Data Source
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AI summary
Provided are an organic light emitting device including: a substrate; a first electrode; a second electrode; and an organic layer interposed between the first electrode and the second electrode and including an emission layer, wherein one of the first electrode and the second electrode is a reflective electrode and the other is a semitransparent or transparent electrode, and wherein the organic layer includes a layer having at least one of the compounds having at least one carbazole group, and a flat panel display device including the organic light emitting device. The organic light emitting device has low driving voltage, excellent current density, high brightness, excellent color purity, high efficiency, and long lifetime.