Aromatic Amine Compound for Light-Emitting Element Efficiency
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Solution Overview
Problem
The existing light-emitting elements using compounds like 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPB) suffer from low singlet-excitation energy, leading to energy transfer issues, particularly with blue light-emitting materials, which decreases luminous efficiency.
Innovation Solution
Aromatic amine compounds with specific structures, such as those expressed by General Formula (1), are used between electrodes in light-emitting elements to prevent energy transfer from light-emitting materials, enhancing luminous efficiency by having a wide band gap and high triplet level, and allowing efficient energy extraction as light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If NPB is used for a layer which is in contact with a light-emitting layer, then the element structure is established, but energy transfer occurs from light-emitting material to NPB causing decrease in luminous efficiency
Solution Approach 1:
The patent changes the energy level parameters of the aromatic amine compound by modifying its molecular structure (introducing specific substituents like carbazole groups, naphthyl groups, and adjusting aryl group configurations) to achieve high singlet-excitation energy and wide band gap, preventing energy transfer to the light-emitting material while maintaining structural stability
Solution Approach 2:
The patent develops composite aromatic amine compounds with specific molecular architectures combining multiple aromatic groups (carbazole, naphthyl, phenyl) and substituent patterns to achieve the desired energy level characteristics that prevent energy transfer while maintaining structural integrity
2Illumination intensity
If a light-emitting material for emitting blue light with high energy level in excited state is used, then short wavelength emission is achieved, but energy is more likely to transfer to NPB decreasing luminous efficiency
Solution Approach 1:
The patent introduces a specially designed aromatic amine compound as an intermediary layer between the blue light-emitting material and other layers. This intermediary has high singlet-excitation energy that acts as an energy barrier, preventing energy transfer from the high-energy blue light-emitting material to NPB, thus maintaining luminous efficiency while enabling blue light emission
3Device complexity
If aromatic amine compounds with low singlet-excitation energy are used, then the compound structure is simplified, but energy transfer occurs causing decrease in luminous efficiency
Solution Approach 1:
The patent systematically modifies the molecular parameters of aromatic amine compounds by introducing electron-withdrawing and electron-donating groups, extending conjugation with specific aromatic systems, and optimizing substituent positions to achieve high singlet-excitation energy. This approach increases molecular complexity but is necessary to prevent energy transfer and maintain luminous efficiency
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 aromatic amine compounds improve luminous efficiency by reducing energy transfer losses and enabling efficient energy extraction, particularly for blue and green light-emitting materials, leading to higher performance in light-emitting elements and devices.
Implementation Method 1
NPB has low singlet-excitation energy and the energy may transfer from a light-emitting material in an excited state
Implementation Method 2
having a wide band gap and high triplet level
Implementation Method 3
allowing efficient energy extraction as light emission
Data Source
AI summary
An object of the present invention is to provide a novel aromatic amine compound, and a light-emitting element, a light-emitting device, and an electronic appliance with high luminous efficiency. An aromatic amine compound expressed by General Formula (1) and a light-emitting element, a light-emitting device, and an electronic appliance formed using the aromatic amine compound expressed by General Formula (1) are provided. By the use of the aromatic amine compound expressed by General Formula (1), the light-emitting element, the light-emitting device, and the electronic appliance can have high luminous efficiency.