OLED Host and Hole Transport Composition for Low-Voltage Emission
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Solution Overview
Problem
Existing organic electroluminescent devices face challenges in achieving low driving voltage while maintaining high luminous efficiency, leading to decreased lifespan and efficiency issues.
Innovation Solution
Incorporating specific compounds in the hole transport zone and light-emitting layer, represented by formulas 1 and 2, respectively, to optimize charge transport and recombination in the organic electroluminescent device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If phosphorescent materials are used to achieve high luminous efficiency, then luminous efficiency is improved, but driving voltage increases and lifespan decreases
Solution Approach 1:
The patent changes the chemical structure parameters of the hole transport materials by introducing specific functional groups (dialkylamino groups, carbazole groups, indolocarbazole groups) and adjusting molecular weight and substituents to optimize the balance between driving voltage and luminous efficiency, resolving the contradiction between high efficiency and low driving voltage
Solution Approach 2:
The patent uses composite material strategies by combining hole transport materials with specific electron transport materials and light-emitting materials in multi-layer structures, where each layer is optimized for its specific function to achieve overall low driving voltage and high luminous efficiency
2Loss of energy
If phosphorescent materials are used to achieve high luminous efficiency, then luminous efficiency is improved, but lifespan decreases
Solution Approach 1:
The patent modifies molecular parameters including introducing steric hindrance groups, adjusting HOMO/LUMO energy levels, and optimizing molecular weight to improve material stability and device lifespan while maintaining high luminous efficiency
Solution Approach 2:
The patent employs small molecular weight hole transport materials that can be easily deposited and replaced, allowing for optimized device structures that extend operational lifespan without sacrificing efficiency
3Power
If hole transport layer with fast hole mobility is used to achieve low driving voltage, then driving voltage is reduced, but luminous efficiency decreases
Solution Approach 1:
The patent applies local quality optimization by designing hole transport materials with specific functional groups positioned at specific locations in the molecule (e.g., dialkylamino groups at specific positions on aromatic rings) to achieve optimal charge transport properties in the hole transport zone while maintaining efficiency
Solution Approach 2:
The patent adjusts key parameters including HOMO energy level, hole mobility, and molecular weight of hole transport materials to achieve the optimal balance between low driving voltage and high luminous efficiency
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 solution provides an organic electroluminescent device with low driving voltage and excellent luminous efficiency, suitable for display and lighting applications.
Implementation Method 1
An organic EL device (OLED) changes electric energy into light by applying electricity to an organic light-emitting material
Data Source
AI summary
The present disclosure relates to an organic electroluminescent device. The organic electroluminescent device of the present disclosure can provide a low driving voltage and excellent luminous efficiency by comprising a specific combination of a host compound and a hole transport material.