Fused Polycyclic Compound for OLED Emission Layer
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Solution Overview
Problem
Current organic electroluminescence displays face challenges in reducing driving voltage, increasing emission efficiency, and extending device lifetime, particularly in achieving stable performance for phosphorescence, fluorescence, and thermally activated delayed fluorescence applications.
Innovation Solution
A light emitting element incorporating a fused polycyclic compound represented by Formula 1, which includes specific substituents and structural features, is used in the emission layer to enhance emission efficiency and element lifetime, with the compound being capable of emitting delayed fluorescence and having a light center wavelength of about 430 nm to 490 nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional materials are used for emission layer, then device structure is simple, but emission efficiency and lifetime are insufficient
Solution Approach 1:
The patent modifies the molecular structure parameters of the emission layer compound by introducing specific heteroatoms (X1 and X2 selected from O, S, Se, NR12, CR13R14, or SiR15R16) and substituent groups (R1 to R16) into the fused polycyclic core. These parameter changes optimize the HOMO-LUMO energy levels, triplet energy, and molecular packing, thereby improving emission efficiency and device lifetime while maintaining reasonable structural complexity.
Solution Approach 2:
The patent employs composite material design by combining a fused polycyclic core structure with specific heteroatom-containing rings and substituent groups. This composite approach creates a material that integrates multiple functional characteristics: the fused core provides structural stability and rigidity, while the heteroatom-containing rings contribute to desired energy levels and the substituent groups control molecular packing and intermolecular interactions, achieving both high emission efficiency and improved device performance.
2Use of energy by stationary object
If driving voltage is reduced, then energy consumption decreases, but emission efficiency and lifetime become insufficient
Solution Approach 1:
The patent optimizes the energy level parameters of the emission layer compound, specifically tuning the HOMO and LUMO levels and triplet energy (ET) through molecular structure design. By selecting appropriate heteroatoms and substituent groups, the compound achieves optimal energy alignment with charge transport layers, enabling efficient charge injection and recombination at lower driving voltages while maintaining high emission efficiency and extended device lifetime.
3Productivity
If intermolecular distance is increased to reduce exciton quenching, then emission efficiency improves, but material structure becomes more complex
Solution Approach 1:
The patent applies local quality modification by introducing specific substituent groups (R1 to R16) at strategic positions on the fused polycyclic core. These local modifications create steric bulk or specific intermolecular interaction patterns that increase the effective intermolecular distance between emission centers, reducing exciton quenching. The heteroatom-containing rings (X1 and X2) also contribute to controlling local molecular packing, achieving reduced quenching without requiring overall structural 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 use of the fused polycyclic compound improves emission efficiency and extends the lifetime of the light emitting element, while also reducing exciton quenching through increased intermolecular distance, thereby enhancing the overall performance of the organic electroluminescence display.
Implementation Method 1
fluorescence emission which use the generating phenomenon of singlet excitons by the collision of triplet excitons (triplet-triplet annihilation, TTA)
Implementation Method 2
the development of materials for thermally activated delayed fluorescence (TADF) utilizing delayed fluorescence phenomenon
Implementation Method 3
reducing exciton quenching through increased intermolecular distance
Data Source
AI summary
A light emitting element of one or more embodiments includes a first electrode, a second electrode provided on the first electrode, and at least one functional layer provided between the first electrode and the second electrode, and including a fused polycyclic compound having at least one sterically bulky substituent.