Dual-Host Emitting-Layer Composition for Organic Element Lifespan
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Solution Overview
Problem
Existing organic electric elements face challenges in achieving efficient energy transfer from host materials to dopant materials, leading to inefficiencies and reduced lifespan, particularly in phosphorescent emitting layers.
Innovation Solution
Incorporating a combination of a first and second host material in the emitting layer, represented by specific compounds, to control the energy barrier and maximize charge balance, thereby enhancing efficiency and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single host material is used in the emitting layer, then the device structure is simple, but the energy transfer efficiency from host to dopant is insufficient and device lifespan is reduced
Solution Approach 1:
The patent employs a composite host material system consisting of a first host material and a second host material in the emitting layer. This composite approach enables synergistic effects where the first host material provides efficient energy transfer to the phosphorescent dopant while the second host material contributes to charge balance and stability, thereby extending device lifespan without excessive complexity
Solution Approach 2:
The patent optimizes the weight ratio parameters of the first and second host materials (specifically ratios between 1:4 to 4:1) to achieve optimal energy transfer efficiency and charge balance. By adjusting these compositional parameters, the system maximizes device lifespan and performance
2Productivity
If the HOMO level of the host material is not optimized, then the material selection is simple, but charge balance in the emitting layer is poor leading to reduced efficiency
Solution Approach 1:
The patent systematically controls the HOMO energy level parameter of the host materials to match with the phosphorescent dopant and adjacent layers. By adjusting the HOMO level within specific ranges and optimizing the host material composition ratio, the system achieves excellent charge balance and high luminous efficiency
3Productivity
If the energy barrier between emitting layer and adjacent layer is high, then the charge injection is easier to control, but the charge balance in the emitting layer is poor
Solution Approach 1:
The patent optimizes the energy barrier parameter at the interface between the emitting layer and adjacent layers by selecting host materials with appropriate HOMO levels and adjusting their compositional ratios. This creates an optimized energy landscape that facilitates smooth charge injection while maintaining excellent charge balance within the emitting layer
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 solution results in high luminous efficiency and low driving voltage with significantly improved device lifespan.
Implementation Method 1
In a phosphorescent organic electric element using a phosphorescent dopant material
Implementation Method 2
many studies have been carried out to identify the energy transfer method from the host material to the dopant material
Implementation Method 3
For fluorescent and phosphorescent host materials, recently we have been studying the increase of efficiency and life span of organic electric elements using TADF (thermal activated delayed fluorescent)
Data Source
AI summary
Provided are an organic electronic element comprising a light emitting layer composed of a mixture of compounds capable of improving luminous efficiency, stability, and lifespan of the element, and an electronic device therefor.