Light-Emitting Element With Segmented Phosphorescent Layers
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Solution Overview
Problem
Current light-emitting devices with organic material layers face challenges in reducing power consumption, particularly in achieving low driving voltage and high efficiency, despite efforts to improve internal and external light emission efficiencies.
Innovation Solution
A light-emitting element with a pair of electrodes and a layer containing an organic compound, where the light-emitting layer has multiple regions with a phosphorescent material as the emission center dispersed in a host material, and a carrier transporting layer is used to reduce power consumption by optimizing the thickness and spacing of these regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the thickness of light-emitting regions is increased to improve light emission efficiency, then internal light emission efficiency is improved, but driving voltage increases and power consumption increases
Solution Approach 1:
The light-emitting layer is divided into multiple thin light-emitting regions (1-10 nm thick) separated by carrier transporting regions, rather than using a single thick light-emitting layer. This segmentation allows efficient light emission from multiple interfaces while maintaining low driving voltage across each thin region.
Solution Approach 2:
Carrier transporting regions are introduced as intermediary layers between the light-emitting regions. These regions facilitate efficient charge carrier transport and injection into the light-emitting regions, enabling low driving voltage operation while maintaining high light emission efficiency.
2Loss of energy
If multiple light-emitting regions are formed to improve light emission efficiency, then internal light emission efficiency is improved, but device complexity increases
Solution Approach 1:
The thickness of light-emitting regions is optimized to a specific range (1-10 nm) to achieve efficient light emission while maintaining simplicity. This parameter optimization allows multiple regions to be effective without proportionally increasing device complexity.
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 results in a light-emitting device with significantly reduced power consumption and lower driving voltage while maintaining high current efficiency, achieved through the strategic use of phosphorescent materials and carrier transporting layers, enhancing light emission efficiency and reducing energy loss.
Implementation Method 1
the light-emitting layer has a plurality of light-emitting regions in which a substance which becomes an emission center is dispersed in a host material
Implementation Method 2
holes are injected to a layer containing an organic material from an electrode functioning as an anode, and electrons are injected to the layer containing an organic material from an electrode functioning as a cathode
Data Source
AI summary
It is an object to provide a light-emitting element which can reduce power consumption. A light-emitting element is provided, which includes a pair of electrodes and a light-emitting layer interposed between the pair of electrodes. The light-emitting layer includes at least a first layer and a second layer, each of the first layer and the second layer includes an emission center and a host material, the emission center is dispersed in the host material, a thickness of each of the first layer and the second layer is 1 nm or more and 10 nm or less, and the first layer is not in contact with the second layer.