Polycyclic Compound Emission Layer for OLED Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current organic electroluminescence display devices face challenges in achieving low driving voltage, high luminous efficiency, and long service life, particularly in the development of materials for light emitting elements that consistently exhibit these characteristics.
Innovation Solution
A light emitting element is designed with a polycyclic compound in the emission layer, specifically incorporating a first compound represented by Formula 1 and optionally a second or third compound, which enhances luminous efficiency and service life by facilitating thermally activated delayed fluorescence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional materials are used in the emission layer, then the device structure is simple, but the luminous efficiency and service life are insufficient
Solution Approach 1:
The emission layer employs a composite material system comprising a polycyclic compound (Formula 1) as the core luminescent material, optionally combined with second compound (Formula HT-1) and/or third compound (Formula ET-1). This composite approach leverages the complementary properties of different materials to achieve high luminous efficiency and extended service life, resolving the contradiction between reliability improvement and device complexity.
Solution Approach 2:
The patent utilizes thermally activated delayed fluorescence (TADF) mechanism by carefully designing the molecular structure of the polycyclic compound with specific heteroatoms (N(R4) or O at positions X1 and X2) and substituent groups (Formula 2). This parameter optimization of molecular structure enables efficient triplet exciton utilization, achieving high luminous efficiency without requiring heavy metal complexes, thus improving reliability while maintaining reasonable device complexity.
2Use of energy by moving object
If phosphorescence emission or TTA delayed fluorescence is used, then luminous efficiency is improved, but the material development complexity increases
Solution Approach 1:
The polycyclic compound is designed to exhibit self-contained TADF characteristics through its molecular structure, eliminating the need for additional host-guest systems or heavy metal complexes typically required for phosphorescence or TTA delayed fluorescence. The compound autonomously achieves efficient triplet exciton utilization and delayed fluorescence emission, simplifying material development while maintaining high luminous efficiency.
Solution Approach 2:
By optimizing the molecular parameters of the polycyclic compound including the heteroatom configuration (X1 and X2 as N(R4) or O), substituent groups (Formula 2 with specific R5-R11 configurations), and ring structures (Formula 1 framework), the patent achieves favorable singlet-triplet energy gap and appropriate excited state lifetimes. This parameter optimization enables efficient TADF without complex material systems, resolving the contradiction between luminous efficiency and material development 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 solution achieves high efficiency and extended service life by utilizing a polycyclic compound in the emission layer, enabling the light emitting element to emit light with a central wavelength in the range of 430 nm to 490 nm, thereby improving luminous efficiency and service life characteristics.
Implementation Method 1
technologies pertaining to phosphorescence emission using triplet state energy or to delayed fluorescence using triplet-triplet annihilation (TTA) in which singlet excitons are generated by the collision of triplet excitons are being developed, and development is currently directed to thermally activated delayed fluorescence (TADF) materials which utilize a delayed fluorescence phenomenon
Implementation Method 2
a so-called self-luminescent light emitting element in which holes and electrons respectively injected from a first electrode and a second electrode recombine in an emission layer, so that a luminescent material of the emission layer emits light
Data Source
AI summary
Embodiments provide a polycyclic compound and a light emitting element that includes the polycyclic compound. The light emitting element exhibits high efficiency and long service life characteristics. The light emitting element includes a first electrode, a second electrode disposed on the first electrode, and an emission layer disposed between the first electrode and the second electrode and including the polycyclic compound, wherein the polycyclic compound is represented by Formula 1, which is explained in the specification: