Blue Light OLED Using Surface Plasmon Coupling
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Solution Overview
Problem
Current blue light emitting materials in OLEDs, such as phosphorescent and fluorescence materials, face efficiency and lifespan issues, hindering the development of high-efficient white light OLED elements.
Innovation Solution
A blue light emitting device structure that employs an organic material layer with a blue shift light emitting sub-layer between metal layers, utilizing surface plasmon coupling to shift the light-emitting spectrum from 490 nm to 550 nm, thereby eliminating the need for traditional blue light emitting materials and enhancing efficiency and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If blue phosphorescent material (FIrpic) is used to achieve high efficiency, then the efficiency reaches 20.4 cd/A, but the life span is merely hundreds of hours
Solution Approach 1:
The patent changes the emission wavelength parameter of the organic material layer from traditional blue (450-480nm) to green-yellow region (500-560nm), and uses surface plasmon coupling to shift the perceived color to blue. This parameter transformation allows achieving high efficiency and long life span while maintaining blue light emission function
Solution Approach 2:
The patent introduces metal layers (first metal layer and second metal layer) as intermediaries that generate surface plasmon resonance to couple with the organic material layer. This intermediary mechanism shifts the emission spectrum and enables high-efficiency blue light emission without using conventional blue phosphorescent materials
2Duration of action of stationary object
If blue fluorescence material is used to achieve long life span (thirty thousand hours), then the life span is extended, but the efficiency deteriorates to only 10.2 cd/A
Solution Approach 1:
The patent transforms the emission wavelength parameter from blue region to green-yellow region (500-560nm) and uses surface plasmon coupling to achieve blue color perception. This allows using stable fluorescence materials with extended life span while maintaining high efficiency through plasmonic enhancement
Solution Approach 2:
The patent replaces the direct blue light emission mechanism with an optical coupling mechanism involving surface plasmons. The metal layers act as optical resonators that transform the emission spectrum, substituting the need for blue-emitting materials with a plasmonic wavelength conversion system
3Power
If all-phosphorescent white light OLED element is used to achieve high efficiency, then the efficiency is high, but the life span is short making it unable to be applied in illumination
Solution Approach 1:
The patent changes the emission wavelength parameter of the organic material layer to green-yellow region (500-560nm) and uses surface plasmon coupling to shift to blue perception. This parameter transformation enables using stable materials with long life span while achieving high efficiency blue emission
Solution Approach 2:
The patent introduces metal layers as intermediaries that generate surface plasmon resonance to couple with the organic material layer, transforming the emission spectrum. This intermediary mechanism enables high efficiency and long life span simultaneously by avoiding direct use of unstable blue phosphorescent materials
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 achieves a high-efficiency white light emission without using blue light emitting materials, improving the lifespan and efficiency of the OLED element by shifting the blue light spectrum through surface plasmon coupling, allowing for the combination with green or red dopants to produce white light.
Implementation Method 1
A peak of a first light-emitting spectrum of the blue shift light emitting sub-layer is shifted to a peak of a second light-emitting spectrum by surface plasmon coupling between the first metal layer and the second metal layer
Data Source
AI summary
A blue light emitting device includes an electrode layer, a first metal layer, a second metal layer formed between the electrode layer and the first metal layer, and an organic material layer formed between the first metal layer and the second metal layer and including a blue shift light emitting sub-layer. A peak of a first light-emitting spectrum of the blue shift light emitting sub-layer, which ranges within 490-550 nm, is shifted to a peak of a second light-emitting spectrum, which is less than 510 nm, by the surface plasmon coupling between the first metal layer and the second metal layer. A light emitting device is further provided, which is sequentially stacked with a first metal layer, an organic material layer having a blue shift light emitting sub-layer, a second metal layer having a metal portion and an opening portion, an electrode layer, and a light emitting layer doped with a dopant material, to emit white light.