Light-Emitting Device With Fused Aromatic EL Materials
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Solution Overview
Problem
Existing light-emitting devices face challenges in efficiently recombining carriers at a desired position in the EL layer, requiring improvements in carrier injection and transport properties, and enhancing device reliability without relying solely on layer stacking.
Innovation Solution
The use of specific organic compounds with fused aromatic rings, such as furan and furopyrazine/furopyrimidine skeletons, in the EL layer, combined with alkali metals, to enhance carrier transport and injection, thereby improving device characteristics and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional materials are used in the EL layer, then multiple stacked layers are required to achieve sufficient device characteristics, but this increases device complexity and manufacturing difficulty
Solution Approach 1:
The patent changes the chemical structure parameters of the organic compound by introducing a furodiazine skeleton with fused aromatic rings. This structural modification fundamentally alters the carrier transport and injection properties, allowing a single layer to achieve the performance that previously required multiple stacked layers, thereby reducing device complexity while maintaining reliability
Solution Approach 2:
The patent employs a composite organic compound combining the furodiazine core structure with specific aromatic ring systems (such as dibenzofuran, dibenzothiophene, or carbazole groups). This composite molecular structure integrates multiple functional characteristics into one material, enabling it to simultaneously provide both electron transport and hole transport capabilities, thus eliminating the need for multiple separate functional layers
2Device complexity
If the light-emitting layer is made thinner to reduce device complexity, then carrier recombination efficiency decreases, but making it thicker increases the number of layers required
Solution Approach 1:
The patent modifies the molecular parameters of the organic compound by incorporating the furodiazine skeleton, which changes the energy levels and carrier mobility characteristics. This allows the material to maintain high carrier recombination efficiency even in a thicker layer configuration, as the enhanced carrier transport properties compensate for the increased thickness, enabling a single thicker layer to replace multiple thinner layers
3Device complexity
If carrier injection property is improved by material selection, then fewer layers are needed, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the material parameters by selecting organic compounds with specific furodiazine-based structures that possess inherently balanced electron and hole transport capabilities. This material parameter optimization reduces the need for complex multi-layer stacking, and the single-layer approach actually simplifies manufacturing by reducing the number of deposition steps and interfaces that require precise alignment, thereby decreasing rather than increasing manufacturing precision requirements
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
This structure allows for improved device performance with fewer layers and a thicker emitting layer, enhancing carrier recombination efficiency and device reliability.
Implementation Method 1
a material that can increase not only a property of carrier transport to the light-emitting layer but also a property of carrier injection from an electrode
Implementation Method 2
Light emission from a singlet excited state is referred to as fluorescence
Implementation Method 3
light emission from a triplet excited state is referred to as phosphorescence
Data Source
AI summary
Provided is a light-emitting device that can have sufficient device characteristics even with a smaller number of stacked layers in an EL layer and a thicker light-emitting layer than a conventional one by using, as an organic compound used for the EL layer of the light-emitting device, a material that can increase not only a property of carrier transport to the light-emitting layer but also a property of carrier injection from an electrode.