Spiro Emission Layer for High-Efficiency Green OLEDs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current organic electroluminescence devices face challenges in achieving high green emission efficiency and long life, particularly in the development of materials for thermally activated delayed fluorescence (TADF) and phosphorescence emission.
Innovation Solution
An organic electroluminescence device incorporating a spiro compound with an aryl amine group and an indenoindole derivative, which forms a spiro bond and has a small difference between its singlet and triplet energy levels, is used in the emission layer to enhance green light emission efficiency and device longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional materials are used in the emission layer, then device structure is simple, but green emission efficiency is low
Solution Approach 1:
The patent employs composite materials by combining the spiro compound (containing aryl amine group and indenoindole derivative) with a host material in the emission layer. This composite approach enables thermally activated delayed fluorescence with high green emission efficiency while maintaining manageable device complexity through systematic material design.
Solution Approach 2:
The patent achieves high green emission efficiency by precisely controlling the energy level parameters of the spiro compound, specifically ensuring the absolute value of the difference between singlet and triplet energy levels is 0.2 eV or less. This parameter optimization enables efficient TADF while keeping the material structure relatively simple.
2Duration of action of stationary object
If conventional emission materials are used, then material selection is simple, but device life is short
Solution Approach 1:
The emission layer uses a composite system of host material and spiro compound dopant, where the spiro compound's specific molecular structure (aryl amine group + indenoindole derivative with spiro bond) provides enhanced stability and longevity. This composite approach extends device life while maintaining reasonable material selection complexity.
Solution Approach 2:
The patent extends device life by optimizing the energy level parameters of the spiro compound, specifically controlling the singlet-triplet energy difference to be 0.2 eV or less. This parameter control enables sustained TADF emission and improved device stability without overly complicating material composition.
3Productivity
If phosphorescence emission technique is used, then emission efficiency can be improved, but device complexity increases
Solution Approach 1:
The patent replaces the phosphorescence emission mechanism (which requires heavy metal atoms and complex spin-orbit coupling) with thermally activated delayed fluorescence. This substitution achieves high emission efficiency through a simpler mechanism based on thermal energy conversion and the specific molecular structure of the spiro compound, reducing device complexity.
Solution Approach 2:
The patent transitions from phosphorescence to TADF by changing the emission mechanism parameters - specifically by designing the spiro compound with a small singlet-triplet energy difference (≤0.2 eV), enabling efficient thermal activation and delayed fluorescence without requiring the complex phosphorescent material system.
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 spiro compound improves the emission efficiency and life of the organic electroluminescence device by facilitating thermally activated delayed fluorescence, achieving high efficiency and long life in the green emission region.
Implementation Method 1
technique on phosphorescence emission which uses energy in a triplet state or delayed fluorescence emission which uses the generating phenomenon of singlet excitons by the collision of triplet excitons (triplet-triplet annihilation, TTA) is being developed, and development on a material for thermally activated delayed fluorescence (TADF) using delayed fluorescence phenomenon is being conducted
Implementation Method 2
delayed fluorescence emission which uses the generating phenomenon of singlet excitons by the collision of triplet excitons (triplet-triplet annihilation, TTA)
Implementation Method 3
the spiro compound may have an absolute value of a difference between a singlet energy level and a triplet energy level of 0.2 eV or less
Data Source
AI summary
An organic electroluminescence device of an embodiment includes a first electrode, a hole transport region on the first electrode, an emission layer on the hole transport region, an electron transport region on the emission layer and a second electrode on the electron transport region, wherein the emission layer includes a spiro compound containing an aryl amine group and an indenoindole derivative, thereby showing high emission efficiency and the emission layer emits green light.