Fluorescent Dopant with Pentacyclic Core for OLED Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current organic electroluminescence display devices face challenges in achieving high luminous efficiency and long service life for light emitting elements, which are crucial for stable and efficient display performance.
Innovation Solution
A light emitting element with a tandem structure is developed, incorporating a first and second electrode with emission layers containing a hole transporting host, an electron transporting host, a phosphorescent sensitizer, and a fluorescent dopant with a pentacyclic fused ring core including a boron atom and heteroatoms, where the fluorescent dopant has a specific energy level difference and is substituted with a pyrenyl group, enhancing the triplet state energy level and molar extinction coefficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional emission layers are used in organic electroluminescence display devices, then the device can be manufactured with standard materials, but the luminous efficiency and service life of the light emitting element are insufficient
Solution Approach 1:
The patent changes the chemical structure parameters of the fluorescent dopant by introducing a pentacyclic fused ring core with specific heteroatoms (boron, nitrogen, oxygen, or sulfur) and pyrenyl group substitutions. This structural parameter change increases the triplet state energy level and molar extinction coefficient, thereby improving luminous efficiency and service life without fundamentally altering the manufacturing process
Solution Approach 2:
The patent creates a composite emission layer system combining hole transporting host, electron transporting host, phosphorescent sensitizer, and the specifically designed fluorescent dopant. This composite material approach optimizes energy transfer between components, enhancing both luminous efficiency and operational stability while maintaining compatibility with existing manufacturing processes
2Illumination intensity
If the triplet state energy level is increased to improve luminous efficiency, then color purity is enhanced, but the energy level difference requirements become more stringent
Solution Approach 1:
The patent systematically adjusts the energy level parameter by modifying the molecular structure of the fluorescent dopant. The pentacyclic fused ring core with heteroatoms and pyrenyl groups provides a built-in energy level framework that ensures the triplet state is at least 0.4 eV higher than the singlet state, achieving color purity while maintaining manufacturability through structured molecular design
Solution Approach 2:
The patent introduces a phosphorescent sensitizer as an intermediary component between the hosts and fluorescent dopant. This sensitizer acts as an energy transfer mediator, facilitating controlled energy transfer to the fluorescent dopant's triplet state while managing the energy level differences, thus reducing the stringency of direct energy level matching requirements
3Productivity
If a tandem structure with multiple emission layers is used to improve luminous efficiency, then the device complexity increases
Solution Approach 1:
The patent divides the light emitting element into multiple emission layers (first emission layer and second emission layer) with different fluorescent dopants optimized for different color regions. This segmentation allows each layer to specialize in specific wavelength emission, improving overall luminous efficiency and color performance while maintaining manageable complexity through modular design
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
This configuration improves luminous efficiency and service life by optimizing energy transfer and emission characteristics, resulting in improved color purity and reproducibility, and extended operational lifespan of the display device.
Implementation Method 1
a phosphorescent sensitizer
Implementation Method 2
a first fluorescent dopant
Implementation Method 3
holes and electrons respectively injected from a first electrode and a second electrode recombine in an emission layer
Data Source
AI summary
Embodiments provide a light emitting element and a display device including the same. The light emitting element includes a first electrode, a second electrode, and a plurality of emission layers disposed between the first electrode and the second electrode, wherein at least one of the plurality of emission layers include a hole transporting host, an electron transporting host, a phosphorescent sensitizer, and a first fluorescent dopant. The first fluorescent dopant comprises a pentacyclic fused ring core that includes one boron atom and two heteroatoms as ring-forming atoms, and at least one amine substituent of the fused ring core; the at least one amine substituent is substituted with at least one substituted or unsubstituted pyrenyl group; and a difference between a triplet state energy level of the first fluorescent dopant and a singlet state energy level of the first fluorescent dopant is equal to or greater than about 0.4 eV.