Triazine Acridine Delayed Fluorescent OLED Emitters
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Solution Overview
Problem
Current organic light emitting diodes (OLEDs) face limitations in emitting efficiency and color purity, particularly due to the use of fluorescent materials which have low external quantum efficiency and lack a reliable blue phosphorescent compound.
Innovation Solution
An organic compound with a triazine moiety as an electron acceptor and a (sila)acridine moiety as an electron donor, connected via a linker, is used as a dopant in the emitting layer, enabling delayed fluorescence and improving emitting efficiency and color purity by separating the highest occupied molecular orbital (HOMO) and low unoccupied molecular orbital (LUMO) energy states, and reducing energy loss through 3D conformation limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fluorescent materials are used in the emitting layer, then the device structure is simple and easy to manufacture, but the external quantum efficiency is low (maximum 25% due to singlet/triplet ratio limitation)
Solution Approach 1:
The patent changes the material parameter from conventional fluorescent emitters to delayed fluorescent emitters with specific molecular structures (containing carbazole, triphenylamine, or triphenylsiline moieties). This parameter change enables both singlet and triplet excitons to contribute to emission through thermally activated delayed fluorescence mechanism, achieving internal quantum efficiency of 100% while maintaining manufacturing simplicity
Solution Approach 2:
The patent uses composite material design by combining specific molecular moieties (carbazole, triphenylamine, triphenylsiline) with electron-accepting groups to create delayed fluorescent emitters. These composite molecular structures achieve both high efficiency and manufacturability
2Use of energy by moving object
If phosphorescent compounds are used to improve emitting efficiency, then the external quantum efficiency increases, but the device lifetime decreases and manufacturing becomes more complex
Solution Approach 1:
The patent replaces expensive, unstable phosphorescent metal complexes with organic delayed fluorescent materials that have longer lifetimes and better stability. These organic compounds achieve comparable or superior efficiency without the reliability issues of phosphorescent materials
Solution Approach 2:
The patent changes the emission mechanism parameter from phosphorescence (metal-complex based) to thermally activated delayed fluorescence (organic molecule based). This parameter change maintains high external quantum efficiency while dramatically improving device lifetime and simplifying manufacturing
3Ease of manufacture
If fluorescent materials are used, then the manufacturing process is simple, but the color purity is insufficient
Solution Approach 1:
The patent changes the molecular structure parameter of the emitter to delayed fluorescent materials with specific chromophores that enable narrow emission bands. This structural parameter change achieves high color purity (narrow FWHM) while maintaining the simplicity of organic material deposition processes
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 organic compound enhances the internal quantum efficiency to 100% by engaging both singlet and triplet excitons in emission, improving the emitting efficiency and color purity of OLEDs, and extending the lifetime of the device.
Implementation Method 1
enabling delayed fluorescence and improving emitting efficiency and color purity by separating the highest occupied molecular orbital (HOMO) and low unoccupied molecular orbital (LUMO) energy states
Implementation Method 2
An organic light emitting diode in the OLED device is formed of a thin organic layer... when the hole from an anode and the electron from the cathode are combined in the EML to generated excitons, and the excitons are transited from an excited state to a ground state such that light is emitted
Data Source
AI summary
Embodiments relate to an organic compound of Formula 1:The excitons in the triplet state are engaged in emission such that the emitting efficiency of the organic compound is increased. Embodiments also relate to an organic light emitting display device with an organic light emitting diode that includes the organic compound.