OLED Filter Layer for Dark Red Emission Shift
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Solution Overview
Problem
Conventional organic light-emitting devices (OLEDs) face challenges in shifting their emission spectrum to the low-energy or high-energy range of the visible spectrum without external converters, as the quantum efficiency of emitter materials increases with wavelength, making it difficult to achieve dark red emission, and using converters reduces efficiency and design flexibility.
Innovation Solution
An organic light-emitting device structure that includes a substrate, a first electrode, an organic functional layer stack emitting in a specific wavelength range, and a filter layer with an absorption range that contains either the low-energy or high-energy sub-range of the emitted radiation, allowing for the attenuation of unwanted spectral regions while maintaining the dominant wavelength, thereby shifting the emission into the dark red range without external converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If converter materials are applied externally onto the OLED to shift the dominant wavelength towards larger wavelengths, then the emission can be shifted into the dark red range, but the appearance and shape design advantage of OLEDs is negatively impacted and color conversion results in a severe reduction in efficiency
Solution Approach 1:
The patent combines the filter layer with existing device components (substrate, electrode, or encapsulation layer) to integrate the wavelength-shifting function within the OLED structure itself, eliminating the need for separate external converter materials and maintaining the device's design advantages
Solution Approach 2:
The filter layer is designed to serve multiple functions: it acts as a structural component of the OLED (substrate, electrode, or encapsulation layer) while simultaneously functioning as a wavelength-selective filter to shift emission into the dark red range, thereby achieving multi-functionality without adding external components
2Illumination intensity
If converter materials are applied externally onto the OLED to shift the dominant wavelength towards larger wavelengths, then the emission can be shifted into the dark red range, but color conversion results in a severe reduction in efficiency
Solution Approach 1:
The patent introduces a filter layer as an intermediary component that selectively absorbs unwanted wavelengths and transmits the desired dark red emission, achieving wavelength conversion without the severe efficiency losses associated with conventional external converter materials
Solution Approach 2:
The filter layer is designed with specific optical parameters (absorption spectrum, thickness, material composition) to selectively transmit dark red wavelengths while blocking other ranges, achieving efficient wavelength conversion by optimizing these parameters rather than relying on inefficient phosphor-based converters
3Illumination intensity
If the quantum efficiency of emitter materials is increased with increasing wavelength, then the emission intensity improves, but achieving dark red emission becomes difficult due to exponential increase in non-radiative rate
Solution Approach 1:
The filter layer acts as a mediator that compensates for the low quantum efficiency of dark red emitter materials by selectively blocking non-radiative pathways and transmitting only the desired dark red emission, thereby achieving stable and intense dark red emission even when the emitter material itself has low efficiency
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 solution enables the organic light-emitting device to achieve a desired color appearance by attenuating high-energy or low-energy sub-regions, enhancing efficiency and maintaining design advantages by using a thin filter layer with tetraazaporphyrin derivatives, which absorbs specific spectral ranges, effectively shifting the dominant wavelength into the dark red range.
Implementation Method 1
the filter layer comprises an absorption range which contains the low-energy or the high-energy sub-range of the first wavelength range
Implementation Method 2
Materials suitable for the organic light-emitting layer are materials which have radiation emission based on fluorescence or phosphorescence
Implementation Method 3
Materials suitable for the organic light-emitting layer are materials which have radiation emission based on fluorescence or phosphorescence
Data Source
AI summary
An organic light-emitting device and a method for producing an organic light-emitting device are disclosed. In an embodiment, the OLED includes a substrate, a first electrode disposed on the substrate, at least one first organic functional layer stack disposed on the first electrode, the first organic functional layer stack configured to emit radiation in a first wavelength range, a second electrode disposed on the first organic functional layer stack and a filter layer arranged in a beam path of the first organic functional layer stack, wherein the first wavelength range comprises a low-energy sub-range and a high-energy sub-range and wherein the filter layer comprises an absorption range containing the low-energy or the high-energy sub-range of the first wavelength range.