Polycyclic Compound Delayed Fluorescence Emission Layer
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Solution Overview
Problem
Current organic electroluminescence display devices face challenges in achieving high light-emitting efficiency and lifespan, particularly in utilizing phosphorescence and delayed fluorescence phenomena effectively.
Innovation Solution
A polycyclic compound represented by Formula 1 is used in the emission layer of a light-emitting element, which includes a first electrode, a second electrode, and a polycyclic compound, along with additional compounds to enhance light-emitting efficiency and stability, facilitating delayed fluorescence emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If phosphorescence emission utilizing triplet state energy is used to improve light-emitting efficiency, then light-emitting efficiency is improved, but material lifespan deteriorates due to triplet exciton accumulation
Solution Approach 1:
The patent converts the harmful accumulation of triplet excitons into a beneficial effect by utilizing triplet-triplet annihilation to generate singlet excitons, which then emit light through delayed fluorescence. This transforms the problematic triplet state accumulation into a useful light-emitting mechanism that improves efficiency while reducing material degradation
Solution Approach 2:
The patent changes the energy state parameters of the emitting material by designing compounds with specific singlet and triplet energy levels that enable efficient triplet-triplet annihilation. By controlling the energy gap between S1 and T1 states and optimizing the density of triplet excitons, the system achieves both high light-emitting efficiency and improved material stability
2Use of energy by moving object
If delayed fluorescence emission utilizing triplet-triplet annihilation is used to improve light-emitting efficiency, then light-emitting efficiency is improved, but device complexity increases
Solution Approach 1:
The patent implements a self-service mechanism where the emitting material itself generates the necessary conditions for delayed fluorescence emission. The triplet excitons generated during operation automatically undergo triplet-triplet annihilation to produce singlet excitons, which then emit light without requiring external intervention or complex auxiliary systems
Solution Approach 2:
The emitting material performs multiple functions simultaneously: it generates triplet excitons through electrical injection, stores energy in the triplet state, facilitates triplet-triplet annihilation, and emits light through delayed fluorescence. This multi-functionality is achieved through careful molecular design of the organic compound with appropriate energy levels and electronic structure
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 lifespan, enabling the production of display devices with superior display quality by leveraging the polycyclic compound's ability to efficiently convert triplet excitons into singlet excitons, thereby extending the material stability and emission layer performance.
Implementation Method 1
delayed fluorescence emission utilizing triplet-triplet annihilation (TTA), in which singlet excitons are generated by collision of triplet excitons
Implementation Method 2
development of a thermally activated delayed fluorescence (TADF) material utilizing a delayed fluorescence phenomenon
Implementation Method 3
organic electroluminescence display devices... that recombines, in an emission layer, holes and electrons respectively injected from a first electrode and a second electrode, thereby causing a light-emitting material of the emission layer to emit light
Data Source
AI summary
Provided is a light-emitting element including a first electrode, a second electrode provided on the first electrode, and an emission layer provided between the first electrode and the second electrode. The emission layer includes a first compound represented by Formula 1 below and thus the light-emitting element exhibits long-lifespan characteristics.