OLED Emission-Assist Compound for Exciton Blocking and Longer Life
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Solution Overview
Problem
Current organic electroluminescent devices face challenges in achieving high efficiency and long lifespan due to charge imbalance and low color purity caused by the transfer of excitons to the hole transport layer, which is exacerbated by the low T1 value of materials used in the hole transport layer, leading to reduced efficiency and shortened lifetime.
Innovation Solution
A compound with a specific molecular structure, represented by Formula 1, is used as an emission-auxiliary layer to optimize energy levels and T1 values between layers, improving hole mobility and interfacial properties, thereby reducing driving voltage and enhancing luminous efficiency, color purity, and lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hole transport layer material with low HOMO value is used, then hole transport capability is improved, but T1 value becomes low causing exciton transfer to the hole transport layer, resulting in charge unbalance and reduced device lifetime
Solution Approach 1:
The patent introduces an emission-auxiliary layer as an intermediary between the hole transport layer and the light emitting layer. This intermediate layer has a HOMO level specifically designed to be between the HOMO energy levels of the hole transport layer and the light emitting layer, preventing direct exciton transfer to the hole transport layer while maintaining hole transport capability. This mediator layer resolves the contradiction by blocking the harmful exciton transfer pathway without compromising the necessary hole transport function.
Solution Approach 2:
The patent modifies the energy level parameters of the emission-auxiliary layer material, specifically designing its HOMO level to fall between the HOMO levels of the adjacent layers. By carefully controlling and changing this energy level parameter, the material prevents exciton transfer to the hole transport layer (which would reduce lifetime) while still allowing effective hole transport, thus resolving the contradiction between ease of operation and device lifetime.
2Productivity
If efficiency is increased by improving organic material layer properties, then driving voltage is lowered and life span increases, but achieving optimal efficiency requires complex optimization of multiple parameters including energy levels, T1 values, mobility, and interfacial properties
Solution Approach 1:
The emission-auxiliary layer serves as a mediator that simultaneously addresses multiple optimization requirements. By positioning this intermediate layer with specifically designed energy levels and T1 values, the patent simplifies the overall optimization process while achieving high luminous efficiency, appropriate driving voltage, and extended device lifetime without requiring complex multi-parameter optimization of the entire organic material layer.
3Productivity
If exciton transfer to hole transport layer occurs, then charge unbalance is caused in the light emitting layer, but this leads to light emission at the interface of the hole transport layer, reducing color purity and efficiency
Solution Approach 1:
The emission-auxiliary layer acts as a protective intermediary that prevents excitons generated in the light emitting layer from transferring to the hole transport layer. By blocking this transfer pathway, the layer prevents charge unbalance and interface emission, thereby maintaining both high luminous efficiency and reliable color purity simultaneously.
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 use of the compound as an emission-auxiliary layer significantly lowers driving voltage, improves luminous efficiency, and extends the lifetime of organic electroluminescent devices by optimizing energy levels and material properties, resulting in improved performance across the device.
Implementation Method 1
In general, an organic light emitting phenomenon refers to a phenomenon that converts electric energy into light energy using an organic material
Implementation Method 2
an exciton is formed by the recombination of the electron and hole within the light emitting layer. However, material used in a hole transport layer has a low T1 value because the material should have a low HOMO value. As a result, the exciton generated in the light emitting layer is transferred to the hole transport layer
Data Source
AI summary
The present invention provides the compound represented by Formula 1, an organic electric element comprising a first electrode, a second electrode, and an organic material layer formed between the first electrode and the second electrode, and electronic device thereof, and by employing the compound represented by Formula 1 in the organic material layer, the driving voltage of the organic electric element can be lowered, and the luminous efficiency and life time of the electric element can be improved.