Perylene Spiro Organic Compound for Blue OLED Efficiency
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Solution Overview
Problem
Conventional organic light emitting diodes (OLEDs) face challenges with low emitting efficiency, particularly in blue emission, and high costs due to the use of rare earth metals in phosphorescent materials, which also have limitations in emitting efficiency and color purity.
Innovation Solution
An organic compound with a perylene core and spiro moiety is used as a dopant in the emitting material layer, enhancing emitting efficiency by involving both singlet and triplet excitons, and improving color purity through energy transfer from a delayed fluorescent dopant to a fluorescent dopant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If phosphorescent material is used to improve emitting efficiency, then both singlet and triplet excitons are involved in emission, but the material becomes very expensive due to inclusion of rare earth metals
Solution Approach 1:
The patent replaces expensive phosphorescent materials containing rare earth metals with organic fluorescent compounds that are cheaper and do not require rare earth elements. The fluorescent compounds achieve acceptable emitting efficiency by utilizing singlet excitons, avoiding the need for costly phosphorescent materials while maintaining functional performance.
Solution Approach 2:
The patent modifies the molecular structure of organic compounds by introducing specific substituents (R1 to R6 groups) on the perylene core to optimize the energy levels and emission properties. This structural parameter change enables the fluorescent compound to achieve higher emitting efficiency without requiring rare earth metals, thus reducing cost while improving performance.
2Loss of energy
If phosphorescent material is used to improve emitting efficiency, then both singlet and triplet excitons are involved in emission, but the material is not adequate for blue emission
Solution Approach 1:
The patent carefully adjusts the molecular structure parameters of the organic compound, specifically the substituents R1 to R6 on the perylene core, to control the HOMO-LUMO energy gap and emission wavelength. This enables precise tuning of the emission color to achieve pure blue emission while maintaining high emitting efficiency through optimized energy level alignment.
Solution Approach 2:
The patent uses a composite approach by combining the perylene core structure with specific aromatic hydrocarbon substituents (such as dibenzofuran, dibenzothiophene, carbazole groups) to create a hybrid molecular structure that achieves both high emitting efficiency and pure blue emission color, overcoming the limitations of simple phosphorescent materials.
3Quantity of substance
If fluorescent material is used then only singlet exciton is involved in emission, but the emitting efficiency is low
Solution Approach 1:
The patent optimizes the molecular structure parameters of the fluorescent compound by selecting specific substituents (R1 to R6) that enhance the radiative decay rate of singlet excitons and improve the overlap between HOMO and LUMO wavefunctions. This structural optimization increases the fluorescent quantum yield and emitting efficiency without requiring triplet exciton involvement, achieving high efficiency through singlet exciton utilization alone.
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 significantly increases the external quantum efficiency of OLEDs by 26.1% compared to devices without fluorescent dopants and 155.4% compared to those with inappropriate energy transfer, while maintaining or improving current and power efficiency, and achieving excellent color purity.
Implementation Method 1
improving color purity through energy transfer from a delayed fluorescent dopant to a fluorescent dopant
Implementation Method 2
The organic light emitting diode emits light by injecting electrons from a cathode as an electron injection electrode and holes from an anode as a hole injection electrode into an organic emitting layer, combining the electrons with the holes, generating an exciton, and transforming the exciton from an excited state to a ground state
Data Source
AI summary
The present disclosure provides an organic compound of following formula and an organic light emitting diode and an OLED device including the organic compound.