Hybrid OLED Structure With Inorganic Blue Emissive Layer Stability
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Solution Overview
Problem
The development of full-color displays using phosphorescent emissive molecules is hindered by the short lifespan of phosphorescent blue OLEDs, which struggle with managing high-energy excited states, and the challenges in producing GaN/InGaN based LEDs for displays due to cost and sheet-scale growth limitations.
Innovation Solution
An organic optoelectronic device is designed with a substrate, a first electrode, a first organic buffer layer, and a first inorganic emissive layer positioned over the organic buffer layer. The inorganic emissive layer can be a blue emissive layer with a multi-quantum well structure, and its distance from the interface with the organic buffer layer is optimized between 2.5 nm and 20 nm, typically around 12 nm. This configuration allows for efficient energy transfer and charge balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If phosphorescent emissive molecules are used for full-color displays, then color saturation is improved, but device lifespan deteriorates due to short lifespan of phosphorescent blue OLEDs
Solution Approach 1:
The patent combines organic and inorganic emissive layers to create a hybrid OLED structure. The inorganic layer (e.g., GaN/InGaN quantum wells) provides stable blue emission with long lifespan, while the organic host material facilitates efficient energy transfer and charge transport, resolving the contradiction between color saturation and device durability
Solution Approach 2:
The organic host material acts as an intermediary between the inorganic emissive layer and the charge transport layers. It receives charges from the electrodes, transports them to the inorganic emitter, and facilitates energy transfer, enabling the inorganic layer to achieve stable blue emission without the lifespan issues of purely organic phosphorescent materials
2Reliability
If GaN/InGaN based LEDs are used for displays, then robustness and efficiency are improved, but manufacturing cost and complexity increase due to sheet-scale growth limitations
Solution Approach 1:
The patent segments the device into distinct functional layers: organic charge transport layers, inorganic emissive layer with quantum wells, and interfacial buffer layers. This segmentation allows each layer to be optimized independently and facilitates modular manufacturing, reducing the complexity of sheet-scale growth while maintaining the robustness of GaN/InGaN-based emission
Solution Approach 2:
The patent applies local quality by using inorganic GaN/InGaN materials specifically in the emissive layer where high efficiency and robustness are critical, while using organic materials in the charge transport layers where flexibility and ease of manufacturing are more important. This localized approach optimizes performance where needed while maintaining 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 proposed device structure enhances the efficiency and stability of blue OLEDs, addressing the short lifespan issue, and combines the cost-effectiveness of organic materials with the robustness of inorganic active layers, potentially leading to improved performance in full-color displays.
Implementation Method 1
The inorganic emissive layer can be a blue emissive layer with a multi-quantum well structure, and its distance from the interface with the organic buffer layer is optimized between 2.5 nm and 20 nm, typically around 12 nm. This configuration allows for efficient energy transfer and charge balance.
Implementation Method 2
OLEDs make use of thin organic films that emit light when voltage is applied across the device.
Data Source
AI summary
An organic electronic optoelectronic device comprises a substrate, a first electrode positioned over the substrate, a first organic buffer layer positioned over the first electrode, and a first inorganic emissive layer positioned over the first organic buffer layer. A method of fabricating an organic optoelectronic device is also disclosed.