Organic Electroluminescent Element Capping Layer for SPP Loss Reduction
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Solution Overview
Problem
Current organic electric elements face challenges in achieving high luminous efficiency, heat resistance, and extended lifetime due to limitations in the organic material layer materials and optical energy loss caused by surface plasmon polaritons (SPP) in the top device structure.
Innovation Solution
An organic electric element is designed with a capping layer on at least one surface of the electrodes, comprising a compound that enhances surface plasma resonance, reducing optical energy loss and improving charge balance, heat stability, and color purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a top device structure with reflective anode is used, then device complexity is reduced, but optical energy loss increases due to surface plasmon polariton
Solution Approach 1:
The patent converts the harmful surface plasmon polariton effect into a beneficial resonance enhancement by introducing a capping layer with specific dielectric constant. The SPP that causes energy loss is transformed into surface plasma resonance that amplifies light emission, turning the harmful optical energy loss into improved luminous efficiency and color purity
Solution Approach 2:
The patent optimizes the dielectric constant parameter of the capping layer material to achieve maximum surface plasma resonance enhancement. By carefully selecting materials with specific dielectric constants (e.g., MgO, Al2O3, SiO2 with different thicknesses), the system tunes the resonance condition to enhance emission in the visible range while minimizing energy loss
2Productivity
If organic material layer is simply improved, then luminous efficiency increases, but lifetime decreases due to Joule heating and crystallization
Solution Approach 1:
The capping layer acts as an intermediary between the organic material layer and the external environment, providing thermal management that prevents excessive Joule heating. This intermediary layer helps dissipate heat while maintaining the optical enhancement benefits, thereby extending device lifetime without sacrificing luminous efficiency
Solution Approach 2:
The patent applies preliminary protective measures by designing the capping layer structure to prevent crystallization of the organic material before it occurs. The controlled thermal environment created by the optimized capping layer configuration preemptively counteracts the crystallization tendency, preserving device performance over extended operation periods
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 implementation of the capping layer with the specified compound achieves high luminous efficiency, heat resistance, and extended lifetime by minimizing SPP losses and optimizing light extraction through constructive interference.
Implementation Method 1
In addition, in this situation, not only the challenge for efficient consumption power but also challenges for luminous efficiency and lifetime must be solved.
Implementation Method 2
In general, an organic light emitting phenomenon refers to a phenomenon where electrical energy is converted into light energy using an organic material.
Implementation Method 3
when a small amount of dopant having a smaller energy band gap than the host of the emitting layer is added to the emitting layer, excitons generated in the emitting layer are transferred to the dopant to generate light with high efficiency.
Implementation Method 4
Compared with the bottom device structure of the non-resonant structure, the top device structure has a large optical energy loss due to surface plasmon polariton (SPP) because the formed light is reflected by the anode, which is a reflective film, and emitted toward the cathode.
Data Source
AI summary
The present disclosure relates to an organic electric element for realizing high luminous efficiency, and high heat resistance of the element, improve the color purity of the element, and increase the lifetime of the element.