Nanostructured OLED Electrodes for Purcell-Enhanced Out-Coupling
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Solution Overview
Problem
Organic opto-electronic devices, such as OLEDs, face challenges in enhancing emission rates, out-coupling efficiency, and device stability, particularly in achieving saturated colors and efficient far-field radiation patterns.
Innovation Solution
Incorporation of nanostructures, including periodic, quasi-periodic, or aperiodic arrays of holes in the electrode layers, which couple electromagnetic modes to surface plasmons, and the use of dielectric layers to optimize the resonance and refractive index, enhancing emission rates and stability while providing controlled far-field radiation patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional OLED structures are used, then device simplicity is maintained, but emission rates and out-coupling efficiency are insufficient
Solution Approach 1:
The patent introduces periodic, quasi-periodic, or aperiodic arrays of holes (nanoporous structures) in the electrode layers. These porous nanostructures serve multiple functions: they increase the surface area for light emission, enhance out-coupling efficiency by providing additional optical pathways, and enable Purcell enhancement through localized electromagnetic field effects. The nanoporous architecture transforms the flat electrode surface into a three-dimensional light-manipulating structure without fundamentally changing the OLED's basic construction.
Solution Approach 2:
The patent transitions from two-dimensional flat electrode surfaces to three-dimensional nanoporous structures by introducing vertical holes through the electrode layers. This dimensional transformation creates additional optical pathways and increases the interaction volume between the emissive layer and the external environment, thereby enhancing emission rates and out-coupling efficiency while maintaining device feasibility.
2Illumination intensity
If white light emission is used, then color coverage is achieved, but saturated colors require additional filtering that reduces efficiency
Solution Approach 1:
The patent applies different nanoporous structures to different regions or layers of the OLED device. By optimizing the hole size, shape, and distribution in specific locations, the device can achieve saturated colors in certain areas while maintaining high overall emission efficiency. The local quality variation allows tailored optical performance without requiring global color filtering.
3Productivity
If nanostructures are added to enhance emission, then out-coupling efficiency improves, but device manufacturing complexity increases
Solution Approach 1:
The patent employs periodic arrays of holes with regular spacing and uniform dimensions. This periodic structure can be fabricated using standard photolithography and etching techniques, making the manufacturing process compatible with existing OLED production lines. The regular pattern simplifies alignment and reduces fabrication variability compared to aperiodic or random nanoporous structures.
Solution Approach 2:
The patent optimizes key parameters of the nanoporous structures, such as hole diameter (e.g., 50-200 nm), depth, and spacing, to achieve maximum out-coupling efficiency. By carefully selecting these parameters within specific ranges, the device attains enhanced performance while remaining compatible with conventional fabrication capabilities. The parameter optimization balances optical performance with manufacturing feasibility.
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 nanostructured OLEDs exhibit improved emission rates, increased surface plasmon polariton out-coupling, and enhanced device stability, along with tailored far-field radiation patterns, effectively addressing the limitations of conventional OLEDs.
Implementation Method 1
nanoparticles, nanorods, nanotubes, nanowires, nanoshells, nanocages, nanostars, nanoflowers, nanoframes, or nanocores, or any combination thereof
Implementation Method 2
The present invention relates to nanostructures to increase emission rates and/or out-coupling, improve device stability, and/or provide a far-field radiation pattern
Implementation Method 3
the use of dielectric layers to optimize the resonance and refractive index, enhancing emission rates and stability
Data Source
AI summary
Embodiments of the disclosed subject matter provide a device including one or more organic layers that include an emissive layer, a first electrode layer disposed over the one or more organic layers, a plurality of nanostructures formed as part of the first electrode layer, a substrate, a second electrode layer, where the second electrode layer is disposed on the substrate, the one or more organic layers are disposed on the second electrode layer, and the first electrode layer including the plurality of nanostructures is disposed on the one or more organic layers and within the predetermined threshold distance of the emissive layer.