Tandem Plasmonic OLEDs with Common Electrode Enhancement
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Solution Overview
Problem
Current organic light-emitting diode (OLED) technologies face challenges in achieving efficient light emission and color accuracy, particularly in tandem structures, where the combination of emissive layers and enhancement layers do not effectively couple excited state energy to surface plasmon polaritons, leading to reduced efficiency and stability.
Innovation Solution
Incorporating a plasmonic enhancement layer with surface plasmon resonance that non-radiatively couples to both emissive layers, transferring excited state energy to surface plasmon polaritons and utilizing an outcoupling layer to convert this energy into photons, thereby enhancing light emission efficiency and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a plasmonic enhancement layer is added to improve light emission efficiency, then internal quantum efficiency is improved, but device complexity increases
Solution Approach 1:
The patent combines the enhancement layer with existing electrode structures (anode or cathode) to form a multi-functional component that serves both electrical and plasmonic functions, thereby reducing overall device complexity while maintaining efficiency improvements
Solution Approach 2:
The enhancement layer is designed to perform multiple functions: it acts as an electrode for charge injection/transport and simultaneously provides plasmonic enhancement for light emission, eliminating the need for separate functional layers
2Productivity
If the enhancement layer is placed closer to the emissive layer to improve coupling, then energy transfer efficiency is improved, but stability deteriorates due to increased non-radiative decay
Solution Approach 1:
The patent optimizes the distance parameter between the enhancement layer and emissive layer to achieve the threshold distance that maximizes radiative coupling while minimizing non-radiative decay, balancing efficiency and stability
Solution Approach 2:
The enhancement layer is positioned specifically at the threshold distance from the emissive layer where radiative coupling is maximized, creating a localized optimal interaction zone that maintains both efficiency and device 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
This approach significantly improves the internal quantum efficiency and stability of OLEDs by effectively coupling excited state energy to surface plasmon polaritons, leading to enhanced light emission and prolonged operational lifetime.
Implementation Method 1
an enhancement layer comprising a plasmonic material exhibiting surface plasmon resonance that non-radiatively couples to the at least one organic emissive material and transfers excited state energy from the non-radiatively-coupled organic emissive material to non-radiative modes of surface plasmon polaritons
Data Source
AI summary
Organic electroluminescent devices are provided, including devices having a tandem structure in which two or more plasmonic OLEDs are arranged in a stack. The plasmonic OLEDs may be inverted or non-inverted. A common electrode disposed between the OLEDs or an outer electrode of the device provides the enhancement layer for one or plasmonic OLEDs in the stack.