OLED Light Emitting Element Using Metal Layer Coupling for White Light
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Solution Overview
Problem
Blue light emitting materials in OLEDs exhibit inferior performance compared to green or red materials, with low luminous efficiency and short lifetime, necessitating the development of high-efficiency white OLEDs that do not rely on blue phosphorescent/fluorescent materials.
Innovation Solution
A light emitting element structure comprising a substrate, multiple metal layers, and organic material layers, where the organic material layers emit light within specific wavelength ranges, and couplings between metal layers shift these wavelengths to achieve a white light output, comprising red, green, and blue light bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blue phosphorescent/fluorescent materials are used in OLEDs, then light emission is achieved, but luminous efficiency is low and lifetime is short
Solution Approach 1:
The patent changes the wavelength parameter of the organic material layer from blue emission to green emission (peak wavelength 500-560nm), and uses metal layer coupling to shift the emitted light wavelength. This parameter change avoids the use of blue phosphorescent/fluorescent materials, thereby improving both luminous efficiency and lifetime while achieving white light output through wavelength shifting
Solution Approach 2:
The patent introduces metal layers (first metal layer and second metal layer) as intermediary components that couple with the organic material layer to shift the peak wavelength of emitted light. These metal layers act as mediators that transform the green emission from the organic material into the desired white light output, eliminating the need for problematic blue emitting materials
2Loss of energy
If blue phosphorescent/fluorescent materials are used in OLEDs, then light emission is achieved, but luminous efficiency is low
Solution Approach 1:
The patent changes the emission wavelength parameter from blue to green (500-560nm) and uses coupling effects to shift the final output wavelength. This parameter transformation achieves high luminous efficiency by avoiding blue phosphorescent/fluorescent materials while maintaining long lifetime through the use of stable green emitting organic materials and metal layer structures
3Illumination intensity
If metal layers are added to shift wavelength, then white light output is achieved, but device complexity increases
Solution Approach 1:
The patent merges the wavelength shifting function directly into the existing OLED structure by integrating metal layers with the organic material layer. The first metal layer and second metal layer are combined with the green-emitting organic material to create a unified structure that simultaneously achieves white light output without requiring separate wavelength conversion components
Solution Approach 2:
The metal layers serve multiple functions: they act as electrodes for electrical connection, provide structural support, and simultaneously function as wavelength-shifting components through coupling with the organic material layer. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving white light emission
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 structure effectively shifts peak wavelengths to produce white light by adjusting metal layer thickness and distance, enhancing luminous efficiency and extending the lifetime of the OLED, while avoiding the use of blue phosphorescent/fluorescent materials.
Implementation Method 1
When a forward biased voltage is applied to the OLED, electrons and holes are injected from a cathode and an anode, respectively, and excitons are formed in a light emitting layer through recombination of electrons and holes. Radiative decay of the excitons results in light emission.
Implementation Method 2
a first coupling is generated between the first metal portion and the second metal layer and shifts the peak wavelength of the light from the first range to a second range
Data Source
AI summary
A light emitting element is disclosed, including a substrate layer, a first metal layer and a second metal layer stacked sequentially on the substrate layer, and an organic material layer disposed between the first metal layer and the second metal layer. The first metal layer includes a first metal portion and a second metal portion that cover a surface of the substrate layer, and an opening portion disposed between the first metal portion and the second metal portion and exposes a portion of the surface. The organic material layer emits light having a wavelength within a first range. A first coupling generated between the first metal portion and the second metal layer shifts the light from the first range to a second range. A second coupling generated between the second metal portion and the second metal layer shifts the light from the first range to a third range.