Light-Emitting Layer Structure for Stable EQE and Wavelength
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Solution Overview
Problem
Existing compositions face challenges in achieving improved layer brightness, optical performance, thermal stability, and durability of cured films, particularly under high UV light intensity, while maintaining a stable peak maximum wavelength and preventing EQE drop after thermal treatment.
Innovation Solution
A novel layer structure with varying light emitting moiety concentration and phase distribution across the layer thickness, combined with a specific matrix material and controlled light emitting moiety concentration in defined areas, is used to enhance film properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform distribution of light emitting moiety is used in the layer, then manufacturing is simple, but layer brightness and optical performance (EQE value) are insufficient
Solution Approach 1:
The patent applies local quality by creating non-uniform concentration distribution of light emitting moieties within the layer. Specifically, the concentration varies in the direction of layer thickness, with higher concentration in certain regions (such as the lower side within 25% of layer thickness from the bottom surface) and lower concentration in other regions. This spatial variation in concentration optimizes both brightness and EQE performance while maintaining manufacturability through controlled deposition processes.
2Productivity
If high UV light intensity is used for curing, then curing speed increases, but peak maximum wavelength shifts to red and EQE value decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the concentration distribution of light emitting moieties as a key parameter. By controlling the concentration to vary in the direction of layer thickness rather than being uniform, the patent achieves optimal curing characteristics. This parameter optimization allows effective curing at moderate UV intensities while maintaining peak wavelength stability and high EQE values, avoiding the harmful effects of high-intensity curing.
3Stability of the object's composition
If thermal treatment is applied to improve film properties, then film quality improves, but peak maximum wavelength shifts to red and EQE value drops
Solution Approach 1:
The patent applies parameter changes by optimizing the concentration distribution of light emitting moieties before thermal treatment. The non-uniform concentration profile (with higher concentration in specific regions) is designed to be compatible with subsequent thermal processing. This allows thermal treatment to improve film quality and morphology without causing significant red shift of peak wavelength or loss of EQE performance.
4Illumination intensity
If light emitting moiety concentration is increased to improve brightness, then layer brightness increases, but EQE value and thermal stability deteriorate
Solution Approach 1:
The patent resolves this contradiction by applying local quality through spatially varying concentration distribution. Instead of uniformly increasing concentration throughout the entire layer (which would harm EQE and thermal stability), the patent concentrates the light emitting moieties in specific regions (such as the lower side within 25% of layer thickness from the bottom surface) while maintaining lower concentration in other regions. This localized high concentration achieves improved brightness without compromising overall EQE value and thermal stability.
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 proposed layer structure achieves higher EQE values, improved thermal stability, and long-term durability, along with a blue shift in peak maximum wavelength, while maintaining film brightness and preventing red shift under high UV light intensity.
Implementation Method 1
one or more light emitting moieties (120)... higher EQE values... blue shift in peak maximum wavelength
Implementation Method 2
cured composition film... after curing the composition... UV light intensity
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2A
AI summary
The present invention relates to a layer comprising at least a matrix material (110) and one or more light emitting moieties (120).