Light-emitting Device Multi-layered Film Interlayer Efficiency
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Solution Overview
Problem
Existing blue light-emitting devices face challenges with low efficiency and short lifespan due to the limitations of fluorescent materials, and blue phosphorescence or delayed fluorescence devices struggle to maintain long-term performance.
Innovation Solution
A light-emitting device is designed with a multi-layered film interlayer consisting of an odd number of layers with different refractive indices, incorporating phosphorescent or delayed fluorescence materials as dopants, and a cascading structure from the hole transport layer to the auxiliary layer to enhance light efficiency and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fluorescent materials are used in blue light-emitting devices, then the device structure is simple, but the efficiency is low and lifespan is short
Solution Approach 1:
The patent employs composite materials by incorporating phosphorescent or delayed fluorescence dopants into the emission layer, combining multiple material types to achieve both high efficiency and extended lifespan while maintaining manufacturability through standardized deposition processes
2Duration of action of stationary object
If phosphorescence or delayed fluorescence materials are used, then the lifespan is extended, but maintaining long-term performance becomes difficult
Solution Approach 1:
The patent applies local quality by creating a multi-layered film structure with specific refractive index variations at different locations within the emission layer, optimizing light extraction and carrier injection at specific interfaces to maintain performance stability throughout the extended device lifespan
Solution Approach 2:
The patent utilizes parameter changes by adjusting the refractive indices of different layers in the multi-layered film structure, optimizing optical properties to maintain stable performance over time while extending device lifespan through phosphorescent or delayed fluorescence materials
3Productivity
If a multi-layered film with different refractive indices is used, then light extraction efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the emission layer into multiple sub-layers with different refractive indices, where each layer performs a specific function in light extraction or carrier transport, improving overall efficiency while keeping each individual layer relatively simple
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 solution improves internal quantum efficiency and extends the lifespan of the light-emitting device by optimizing light generation through constructive interference and efficient carrier injection, while maintaining suitable driving voltage characteristics.
Implementation Method 1
optimizing light generation through constructive interference
Implementation Method 2
Carriers, such as holes and electrons, recombine in the emission layer to produce light
Data Source
AI summary
A light-emitting device includes: a first electrode; a second electrode facing the first electrode; and an interlayer arranged between the first electrode and the second electrode, the interlayer including an emission layer,wherein the interlayer includes a multi-layered film consisting of an odd number of layers, and the multi-layered film is formed by alternately stacking layers having different refractive indices from each other.