Fused Polycyclic Compound for OLED Emission Layer
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Solution Overview
Problem
Current organic electroluminescence display devices face challenges in achieving low driving voltage, high emission efficiency, and long service life, particularly in developing materials that consistently meet these criteria.
Innovation Solution
A light emitting element is designed with a fused polycyclic compound represented by Formula 1, which includes a specific structure of fused aromatic rings through a boron atom and nitrogen atoms, used in the emission layer to enhance emission efficiency and service life, incorporating additional compounds like those represented by Formulas HT-1, ET-1, and D-1 to form an exciplex or serve as a phosphorescent sensitizer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional organic electroluminescence materials are used, then the device can achieve basic light emission, but the emission efficiency and service life are insufficient
Solution Approach 1:
The patent employs composite material strategy by combining the fused polycyclic compound (Formula 1) with host materials (Formulas HT-1, ET-1) and phosphorescent sensitizers (Formula D-1) to create an exciplex emission system. This composite approach enables simultaneous achievement of high emission efficiency through exciplex formation and extended service life through suppressed Dexter energy transfer and trap-assisted recombination.
Solution Approach 2:
The patent utilizes parameter changes by modifying the HOMO energy level to achieve a deep HOMO level configuration. This parameter optimization enables efficient energy transfer while maintaining desired emission wavelength, thereby improving both emission efficiency and device stability for extended service life.
2Productivity
If materials are optimized for high emission efficiency, then light output improves, but driving voltage increases and service life decreases
Solution Approach 1:
The patent optimizes energy level parameters by achieving a deep HOMO level configuration through the specific fused polycyclic compound structure. This parameter optimization enables efficient energy transfer and maintains appropriate driving voltage while achieving high emission efficiency through exciplex formation.
3Productivity
If triplet state energy is utilized through phosphorescence emission, then emission efficiency improves, but triplet concentration increases causing reduced service life
Solution Approach 1:
The patent converts the harmful effect of triplet concentration accumulation into a beneficial mechanism by utilizing triplet-triplet annihilation (TTA) to generate singlet excitons that produce delayed fluorescence. This approach maintains high emission efficiency while avoiding the detrimental effects of accumulated triplet states on device service life.
Solution Approach 2:
The patent introduces an intermediary mechanism where the fused polycyclic compound acts as a mediator between triplet excitons and singlet emission. Through TTA processes, triplet excitons are converted to singlet excitons that can emit light without the harmful accumulation effects, thereby extending device service life.
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 improves light emitting efficiency and extends the service life of the light emitting element by suppressing Dexter energy transfer and trap-assisted recombination, achieving a deep HOMO energy level and efficient energy transfer, while maintaining a desired emission wavelength.
Implementation Method 1
Development is presently directed to thermally activated delayed fluorescence (TADF) materials which use delayed fluorescence phenomenon
Implementation Method 2
fluorescence emission, which uses triplet-triplet annihilation (TTA) in which singlet excitons are generated through collision of triplet excitons
Implementation Method 3
Distance between adjacent molecules increases with the introduction of steric hindrance and bulky substituents, and accordingly, Dexter energy transfer may be suppressed to prevent lifespan deterioration caused by an increase in triplet concentration
Implementation Method 4
The fused polycyclic compound has a deep HOMO energy level, and accordingly, trap-assisted recombination may be suppressed to further improve lifespan of a light emitting element
Implementation Method 5
achieving a deep HOMO energy level and efficient energy transfer, while maintaining a desired emission wavelength
Data Source
AI summary
Embodiments provide fused polycyclic compound and a light emitting element that includes the fused polycyclic compound. The light emitting element include a first electrode, a second electrode facing the first electrode, and an emission layer disposed between the first electrode and the second electrode and including the fused polycyclic compound. The fused polycyclic compound is represented by Formula 1, which is explained in the specification: