OLED Emissive Layer Host Material Blue Light Intensity
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Solution Overview
Problem
Current OLED technologies face limitations in enhancing blue emission intensity and color temperature, leading to suboptimal luminous properties and viewing angles, particularly in achieving efficient white emission.
Innovation Solution
The organic light emitting diode (OLED) incorporates a multi-layered emissive structure with specific charge generation layers and host materials in the blue emitting material layer, featuring a unique chemical formula for the host, which enhances blue light intensity and maintains balanced emission colors, thereby improving color temperature and viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If fluorescent material is used in OLED, then device structure is simple, but luminous efficiency is low due to use of only singlet excitons
Solution Approach 1:
The patent employs a composite emissive layer structure combining fluorescent and phosphorescent materials. The emissive layer includes a fluorescent host material and a phosphorescent dopant, allowing both singlet and triplet excitons to contribute to light emission. This composite approach increases luminous efficiency by utilizing both exciton types while maintaining a relatively simple layered device structure.
2Loss of energy
If phosphorescent material is used to improve luminous efficiency, then luminous efficiency increases, but luminous lifespan decreases for commercial use
Solution Approach 1:
The patent applies local quality by using phosphorescent material specifically in the emissive layer dopant while maintaining a fluorescent host matrix. This localized phosphorescent contribution enhances efficiency without requiring the entire device structure to be phosphorescent, thereby extending operational lifespan. The fluorescent host provides structural stability and long lifetime, while the phosphorescent dopant contributes to high efficiency.
3Illumination intensity
If conventional OLED structure is used, then manufacturing is easier, but blue emission intensity is insufficient for optimal color temperature
Solution Approach 1:
The patent modifies the emissive layer parameters by introducing a specific phosphorescent dopant with controlled emission characteristics. The dopant concentration, host-guest energy level matching, and layer thickness are optimized to enhance blue emission intensity. These parameter adjustments enable achieving optimal color temperature while maintaining manufacturability through a systematic approach to material selection and layer configuration.
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 significantly boosts blue light intensity and color temperature, resulting in improved luminous properties and viewing angles, enabling efficient white emission with balanced red, green, and blue light emission.
Implementation Method 1
The OLED may be driven at a lower voltage and the OLED has advantageous high color purity compared to the LCD
Implementation Method 2
a blue emitting material layer disposed between the red emitting material layer and the second electrode, and wherein the blue emitting material layer comprises a blue emitter and a first host
Data Source
AI summary
The present disclosure relates to an organic light emitting diode (OLED) where an emissive layer comprises four emitting parts each of which is sequentially disposed between a first electrode and a second electrode; and charge generation layers each of which is disposed between emitting parts, where one emitting part comprises a red emitting material layer and a blue emitting material layer comprising a blue emitter and a host having a high HOMO and/or a LUMO energy levels. The OLED may implement efficient white emission by improving the blue emission intensity and/or blue temperature.