OLED Emission Layer Structure for Longer Lifespan and Energy Transfer
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Solution Overview
Problem
Existing organic light-emitting devices (OLEDs) face issues with the deterioration of the emission layer material, leading to reduced lifespan characteristics.
Innovation Solution
Incorporating a spacing layer with an emission layer and at least one of an emission auxiliary layer and a buffer layer, which includes specific emissive compounds and host compounds, where the onset emission wavelength relationships and energy transfer mechanisms enhance emission efficiency and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a conventional emission layer structure is used, then the device structure is simple, but the emission layer material deteriorates leading to reduced lifespan
Solution Approach 1:
The emission layer is divided into multiple functional sub-layers: a first emission layer containing a first emissive compound, and a second emission layer containing a second emissive compound with different emission characteristics. This segmentation allows each sub-layer to perform specific functions, improving overall device lifespan while managing complexity through modular design
Solution Approach 2:
The patent introduces a vertical stacking dimension by placing multiple emission layers at different positions between the electrodes. Each emission layer operates at a different spatial level, enabling independent optimization of materials and emission properties without horizontal interference, thus extending lifespan through dimensional separation
2Use of energy by moving object
If multiple emissive compounds are used in the emission layer, then emission efficiency is improved, but the device structure becomes more complex
Solution Approach 1:
A host compound is introduced as an intermediary material that facilitates energy transfer between the first and second emissive compounds. The host compound accepts energy from one emissive compound and transfers it to another, improving emission efficiency while maintaining a manageable structural organization through this mediating role
Solution Approach 2:
The emission layer is constructed as a composite system combining multiple emissive compounds with different emission characteristics (e.g., phosphorescent and fluorescent compounds) within a host matrix. This composite approach enables synergistic energy transfer and improved overall emission efficiency while managing complexity through systematic material combination
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 emission efficiency and extends the lifespan of OLEDs by effectively transferring energy between emissive compounds, resulting in enhanced performance.
Implementation Method 1
an onset emission wavelength of the first emissive compound may be shorter than an onset emission wavelength of the third emissive compound
Data Source
AI summary
Provided are a light-emitting device and an electronic apparatus including the light-emitting device. The light-emitting device includes a first electrode, a second electrode facing the first electrode, and an interlayer disposed between the first electrode and the second electrode. The interlayer includes an emission layer and at least one of an emission auxiliary layer and a buffer layer, the emission layer includes a host and a dopant, the dopant includes a first emissive compound and a second emissive compound, and the at least one of the emission auxiliary layer and the buffer layer includes a third emissive compound.