Organic Light-Emitting Component Nanoparticle Refractive Index Control
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Solution Overview
Problem
Organic light-emitting components face inefficiencies in light coupling-out due to refractive index differences between organic layers and downstream materials, leading to reflected and internally reflected light that cannot be effectively extracted.
Innovation Solution
Incorporating nanoparticles with a refractive index lower than the organic materials into the organic layer sequence, specifically with diameters less than a quarter of the wavelength at the intensity maximum, to reduce the overall refractive index and prevent scattering, thereby enhancing light coupling-out efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If organic layers with high refractive index are used to achieve desired optical properties, then light emission can be controlled, but light coupling-out efficiency deteriorates due to total internal reflection at interfaces
Solution Approach 1:
The patent introduces nanoparticles with refractive indices between 1.3 and 1.7 into the organic light-emitting layer, changing the effective refractive index parameter of the layer. This gradual transition reduces the refractive index contrast at interfaces, thereby decreasing total internal reflection and improving light coupling-out efficiency while maintaining light emission control
Solution Approach 2:
The nanoparticles act as an intermediary medium between the high refractive index organic materials and the lower refractive index encapsulation materials. By providing intermediate refractive index values, they facilitate gradual light transition and reduce abrupt reflections at material interfaces
2Loss of energy
If nanoparticles with larger diameters are used to reduce refractive index, then light coupling-out efficiency improves, but light scattering increases reducing overall performance
Solution Approach 1:
The patent specifies controlling the nanoparticle diameter parameter to be less than one-quarter of the emission wavelength (typically 20-200 nm). This parameter constraint ensures that nanoparticles remain below the scattering threshold while still effectively modifying the refractive index, thus improving light coupling-out without significant scattering losses
3Loss of energy
If separate light-converting layers are added to improve light extraction, then coupling-out efficiency improves, but device complexity and manufacturing steps increase
Solution Approach 1:
The patent merges the light emission function and the light extraction enhancement function into a single integrated layer. By incorporating light-scattering nanoparticles directly into the organic light-emitting layer, the structure simultaneously performs light generation and light extraction improvement, eliminating the need for separate conversion or extraction layers
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 approach improves light coupling-out efficiency, allowing for higher light power output with reduced input power, and simplifies the production process by avoiding the need for separate light-converting layers, while also enabling more flexible color locus setting through nanoparticle materials.
Implementation Method 1
Incorporating nanoparticles with a refractive index lower than the organic materials into the organic layer sequence, specifically with diameters less than a quarter of the wavelength at the intensity maximum, to reduce the overall refractive index and prevent scattering
Implementation Method 2
Organic light-emitting components face inefficiencies in light coupling-out due to refractive index differences between organic layers and downstream materials, leading to reflected and internally reflected light that cannot be effectively extracted
Data Source
AI summary
An organic light-emitting component (100) is specified, which comprises a carrier (1) and an organic layering sequence (2) arranged on the carrier (1). The organic layering sequence (2) comprises at least two organic layers, wherein at least one of the organic layers is designed as an emitting layer (23). The emitting layer (23) emits light (200) of a first wavelength range, which has an intensity maximum at a first wavelength. Further, the organic light-emitting component (100) comprises an anode (3) and a cathode (4) which provide the electrical contacting of the organic layering sequence (2). Further, the organic light-emitting component (100) has at least one nanoparticle layer (20), wherein one nanoparticle layer (20) is an organic layer of the organic layering sequence (2) provided with first nanoparticles (5). The first nanoparticles (5) have a refractive index (nN) that is smaller than at least one refractive index of an organic material of one of the organic layers. Further, at least one nanoparticle layer (20) is not in direct contact with the anode (3). In addition, the first nanoparticles (5) have a diameter that is smaller than one-fourth of the first wavelength at which the light (200) emitted by the emitting layer (23) has an intensity maximum.