Single-Layer Organic EL Device Using Dual-Function Dye
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Solution Overview
Problem
Current organic electroluminescence (EL) devices with a multi-layer structure require precise control of film thickness and are costly to produce, and single-layer structures face challenges in achieving sufficient emission efficiency at low driving voltage.
Innovation Solution
A single-layer organic EL device using an organic compound with both hole-transporting and electron-transporting abilities, where a charge-transporting group is bonded to light-emitting groups, enhancing conductivity and recombination efficiency, allowing light emission at low voltage without a multi-layer structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a multi-layer structure is employed to improve emission efficiency, then light emission efficiency is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines hole-transporting and electron-transporting functions into a single organic compound layer. The organic compound is designed with both hole-transporting ability and electron-transporting ability, allowing it to perform multiple functions simultaneously. This merging of functions into a single layer eliminates the need for separate hole transport layer and electron transport layer, thus reducing device complexity while maintaining emission efficiency.
Solution Approach 2:
The organic compound used in the single-layer structure possesses universal functionality by exhibiting both hole-transporting and electron-transporting capabilities. This multi-functional material replaces what would traditionally require multiple specialized layers, simplifying the device structure while achieving the necessary charge transport functions for efficient light emission.
2Productivity
If a multi-layer structure is used to enhance charge recombination efficiency, then light emission efficiency is improved, but manufacturing time and cost increase
Solution Approach 1:
The patent merges multiple functional layers into a single organic compound layer that performs both hole transport and electron transport functions. This consolidation reduces the number of film formation steps from multiple sequential depositions to a single layer formation process, significantly reducing manufacturing time while maintaining the charge recombination efficiency needed for high emission efficiency.
3Device complexity
If a single-layer structure is used to simplify manufacturing, then device complexity is reduced, but emission brightness is insufficient
Solution Approach 1:
The patent achieves sufficient emission brightness in a single-layer structure by optimizing the molecular parameters of the organic compound. The compound is designed with specific charge-transporting groups and light-emitting groups in defined configurations, and the concentrations of these groups are carefully controlled. These parameter optimizations enable the single layer to achieve both adequate charge transport and sufficient emission brightness.
Solution Approach 2:
The organic compound functions as a composite material integrating charge-transporting moieties and light-emitting moieties within a single molecular structure. This composite approach allows the material to simultaneously perform multiple functions (hole transport, electron transport, and light emission) that would traditionally require separate layers, achieving sufficient emission brightness while maintaining structural simplicity.
4Device complexity
If organic compounds with both hole-transporting and electron-transporting abilities are used in a single-layer structure, then device complexity is reduced, but driving voltage becomes excessively high
Solution Approach 1:
The patent applies local quality by creating distinct regions within the single-layer structure through the spatial distribution of different functional groups. The organic compound contains charge-transporting groups and light-emitting groups in specific configurations that create local zones optimized for charge transport versus light emission. This local differentiation within the unified layer enables efficient charge recombination at controlled locations, reducing the driving voltage required while maintaining structural simplicity.
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 device achieves sufficient emission brightness at a low driving voltage, simplifying production and reducing costs while maintaining efficiency comparable to multi-layer structures.
Implementation Method 1
X is a n-valent charge-transporting group
Implementation Method 2
light is emitted when the dye is relaxed from an excited state to a ground state
Data Source
AI summary
Disclosed is an organic EL dye enabling to provide an organic EL device which is capable of emitting a light at a low voltage even when it has a single layer structure. Also disclosed is an organic EL device using such an organic EL dye. The organic EL dye is represented by the general formula (1): (Y—L)nXm wherein x is an n-valent charge-transporting group, Y is a light-emitting group, L is a linking group bonding the charge-transporting group and the light-emitting group, and m and n are respectively an integer not less than 1.