Light Emitting Element Using Fused Polycyclic Boron Compound
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Solution Overview
Problem
Current organic electroluminescence display devices face challenges in reducing driving voltage and increasing emission efficiency and lifetime, particularly in developing materials that stably achieve these requirements.
Innovation Solution
A light emitting element is designed with an emission layer comprising a specific fused polycyclic compound and other compounds, such as a second, third, and fourth compound, which are carefully formulated to enhance delayed fluorescence and improve the light emitting central wavelength, emission efficiency, and element lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional organic electroluminescence materials are used, then the device can achieve basic light emission, but the element lifetime and emission efficiency are insufficient
Solution Approach 1:
The emission layer employs a composite material system consisting of a host compound (Formula HT or ET) and a dopant compound (Formula 1) in specific weight ratios (0.1-10 wt% dopant). This composite structure enables synergistic effects where the host provides structural stability and the dopant enhances emission properties, achieving both extended lifetime and maintained emission efficiency through material composition optimization
Solution Approach 2:
The invention optimizes critical parameters including the weight ratio of dopant to host (0.1-10 wt%), the molecular structure parameters of Formula 1 compounds (substituents R1-R7, ring structures), and the HOMO/LUMO energy level parameters. These parameter adjustments fine-tune the emission characteristics and stability, resolving the contradiction between lifetime and emission efficiency by finding optimal parameter ranges
2Reliability
If phosphorescence emission or TADF materials are used to increase emission efficiency, then light output improves, but element lifetime decreases
Solution Approach 1:
The invention applies local quality optimization by designing the dopant compound (Formula 1) with specific local molecular structures (substituents R1-R7 at specific positions) that concentrate emission enhancement properties in the dopant molecules while the host molecules maintain structural stability. This localized functional differentiation allows TADF emission efficiency improvement without compromising overall device lifetime
Solution Approach 2:
The host compound (Formula HT or ET) acts as an intermediary between the dopant and the electrical excitation source. It receives electrical energy, undergoes triplet-triplet annihilation to generate singlet excitons, and transfers energy to the dopant for delayed fluorescence emission. This intermediary mechanism enables efficient emission while protecting the dopant from direct electrical stress, extending element lifetime
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 effectively increases the lifetime of the light emitting element while maintaining high emission efficiency and color purity, addressing the limitations of existing materials by utilizing a specific compound formulation in the emission layer.
Implementation Method 1
delayed fluorescence emission which uses the generating phenomenon of singlet excitons by the collision of triplet excitons (triplet-triplet annihilation, TTA)
Implementation Method 2
triplet-triplet annihilation, TTA
Data Source
AI summary
A light emitting element that includes a first compound represented by a specific chemical formula in which an ortho-type or kind penta-phenyl group is bonded to a fused polycyclic compound including at least one boron atom and a heteroatom is provided. The light emitting element has a long-lifetime.