Polycyclic Compound Emission Layer for OLED Efficiency and Lifespan
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Solution Overview
Problem
Current organic electroluminescence display devices face challenges in achieving low driving voltage, high luminous efficiency, and long service life, with existing materials failing to stabilize these characteristics effectively.
Innovation Solution
A light emitting element is developed with an emission layer containing specific polycyclic compounds, including a first compound represented by Formula 1, and optionally a second, third, or fourth compound, which enhance luminous efficiency and service life by facilitating delayed fluorescence emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional organic electroluminescence materials are used, then the device can operate, but luminous efficiency and service life remain insufficient
Solution Approach 1:
The patent modifies molecular parameters of the organic compounds by introducing specific heteroatoms (O, S, Se, or NRa) at defined positions in the polycyclic framework, and by controlling substituent patterns (R1-R11) to optimize the balance between luminous efficiency and service life. This chemical parameter modification enables simultaneous improvement of both performance metrics.
Solution Approach 2:
The emission layer employs a composite material system combining the novel polycyclic compound (Formula 1) with auxiliary compounds (Formulas HT, ET, or D-1) to achieve synergistic effects. This composite approach allows the system to simultaneously achieve high luminous efficiency through enhanced exciton management and extended service life through improved material stability.
2Use of energy by moving object
If driving voltage is reduced, then energy consumption decreases, but maintaining high luminous efficiency becomes difficult
Solution Approach 1:
The patent optimizes the energy level parameters of the organic compounds by adjusting the electronic structure through heteroatom selection and substituent positioning. This enables the material to achieve efficient exciton generation and radiative decay at lower applied voltages, simultaneously reducing energy input requirements while maintaining high luminous efficiency.
3Productivity
If phosphorescence emission techniques are used to improve efficiency, then triplet state energy utilization increases, but material stability and service life may be compromised
Solution Approach 1:
The patent carefully controls the energy gap parameter (ΔEST) between singlet and triplet states to be 0.2 eV or less, enabling efficient thermally activated delayed fluorescence. This parameter optimization allows the system to utilize triplet state energy through thermal activation to generate singlet excitons, achieving high luminous efficiency comparable to phosphorescence while avoiding the stability issues associated with heavy metal phosphorescent materials.
Solution Approach 2:
The patent converts the potentially harmful accumulation of triplet excitons, which can cause degradation, into a beneficial mechanism by utilizing triplet-triplet annihilation to generate singlet excitons that emit light. This transforms what would be a degradation pathway into a productive light-emitting channel, simultaneously improving efficiency and extending 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 proposed solution achieves improved luminous efficiency and extended service life for the light emitting element, specifically through the use of thermally activated delayed fluorescence materials that optimize energy transfer and reduce exciton accumulation, thereby enhancing the overall performance of the organic electroluminescence display device.
Implementation Method 1
techniques of phosphorescence emission, which uses energy in a triplet state, or delayed fluorescence emission, which uses the phenomenon of generating singlet excitons by the collision of triplet excitons (triplet-triplet annihilation, TTA), are being developed, and development of a material for thermally activated delayed fluorescence (TADF) using delayed fluorescence phenomenon is being conducted
Implementation Method 2
delayed fluorescence emission, which uses the phenomenon of generating singlet excitons by the collision of triplet excitons (triplet-triplet annihilation, TTA)
Data Source
AI summary
Provided is a light emitting element includes a polycyclic compound in which an electron donor substituent, which may increase the photoluminescence quantum yield (PLQY) and oscillator strength (f), is introduced at the para-position of a boron atom, thereby exhibiting high efficiency and long service life characteristics.