White Light Emitting Device Dopant Triplet Energy Optimization
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Solution Overview
Problem
Current self-emission display devices face limitations in emission efficiency, color temperature, and visibility, particularly in tandem devices with multiple stacked layers, where achieving high resolution and integration while maintaining vivid color representation is challenging.
Innovation Solution
A white light emitting device is designed with a specific arrangement of emission layers, where the triplet energy levels of dopants are adjusted to improve efficiency and color temperature, featuring a first blue dopant with a triplet energy level equal to or higher than the green dopant, and a phosphorescent stack with emission layers emitting different colors to enhance color representation and visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple stacks are stacked to achieve high resolution and high integration, then device integration is improved, but emission efficiency deteriorates
Solution Approach 1:
The patent adjusts the triplet energy levels of dopants in emission layers as a key parameter to optimize emission efficiency. Specifically, the blue dopant is designed with a triplet energy level equal to or higher than the green dopant, which prevents energy loss through triplet-triplet energy transfer and improves overall emission efficiency in the stacked device configuration.
2Productivity
If multiple stacks are stacked to achieve high resolution and high integration, then device integration is improved, but color temperature deteriorates
Solution Approach 1:
The patent optimizes the triplet energy level parameter of the blue dopant to be equal to or higher than that of the green dopant. This parameter adjustment ensures that the blue emission maintains appropriate intensity and energy characteristics, thereby achieving a balanced color temperature in the white light emitting device despite the complex stacked structure.
3Productivity
If multiple stacks are stacked to achieve high resolution and high integration, then device integration is improved, but visibility deteriorates
Solution Approach 1:
By adjusting the triplet energy level parameter of the blue dopant to be equal to or higher than the green dopant, the patent optimizes the energy distribution across different emission layers. This results in improved blue light emission intensity and overall visibility, ensuring that the stacked device maintains vivid color representation and high visibility despite the increased structural complexity.
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 significantly improves blue light emission efficiency, increases color temperature, and enables rich color representation, resulting in improved visibility and eye-friendly cool white light emission.
Implementation Method 1
a first stack disposed between the first electrode and a first charge generation layer, the first stack including a first emission layer including a first blue dopant
Implementation Method 2
a second stack disposed between the first charge generation layer and the second electrode, the second stack including a second emission layer including a red dopant, a third emission layer including a yellowish-green dopant, and a fourth emission layer including a green dopant
Data Source
AI summary
A white light emitting device and a light emitting display device including the same, in which the relationship between the triplet energy levels of dopants of emission layers is appropriately adjusted so as to improve the efficiency of the white light emitting device and the light emitting display device, thereby increasing a color temperature and enabling rich color representation.