Polycyclic Aromatic OLED Layers for Hole Injection and Low-Voltage Emission
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Solution Overview
Problem
Existing organic light-emitting devices face challenges in achieving high luminous efficacy and efficient operation at low voltages, necessitating the development of improved materials and structures for the hole injection and light-emitting layers.
Innovation Solution
Incorporation of specific polycyclic aromatic compounds in the hole injection and transport layers, along with tailored dopants in the light-emitting layer, to enhance hole injection and transport efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional organic compounds are used in the hole injection layer or hole transport layer, then the device can operate, but the external quantum efficiency and luminous efficacy are insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the molecular structure of organic compounds in the hole injection layer or hole transport layer. Specifically, it uses compounds with particular molecular weights, functional groups, and structural configurations (such as dibenzofuran, dibenzothiophene, or carbazole derivatives) to optimize hole transport properties. This structural parameter optimization enables the device to achieve external quantum efficiency of 25% or higher and luminous efficacy of 100 cd/A or higher, directly resolving the efficiency limitations of conventional compounds.
2Ease of operation
If the driving voltage is reduced to improve ease of operation, then the device becomes easier to operate, but the luminous efficacy decreases
Solution Approach 1:
The patent resolves this contradiction by changing the electrical and optical parameters of the organic compounds used in the hole injection layer or hole transport layer. It employs compounds with specifically optimized HOMO levels, LUMO levels, and charge carrier mobility that enable efficient hole injection and transport at low voltages. This parameter optimization allows the device to operate at low driving voltages while maintaining high luminous efficacy, eliminating the trade-off between ease of operation and energy efficiency.
3Loss of energy
If new polycyclic aromatic compounds are introduced to improve efficiency, then external quantum efficiency increases, but the device complexity increases
Solution Approach 1:
The patent applies composite materials by combining polycyclic aromatic compounds with specific functional groups (such as carbazole, dibenzofuran, or dibenzothiophene) in the hole injection layer or hole transport layer. These composite organic compounds are designed to work synergistically with other device components (electron transport materials, light-emitting materials, and electrodes) to achieve high external quantum efficiency. The composite material approach allows the patent to improve efficiency while managing device complexity through systematic material design and layer configuration.
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 proposed configuration enables organic light-emitting devices to operate at lower voltages with significantly improved external quantum efficiency and luminous efficacy.
Implementation Method 1
the structure of the organic layer in the organic light-emitting device should be optimized, and the material constituting each organic layer, namely, a hole injection material, a hole transport material, a light-emitting material, an electron transport material, an electron injection material, or an electron blocking material should be based on stable and efficient ingredients
Implementation Method 2
An organic light-emitting device is a self-luminous device that emits light when energy is released from excitons which are formed by recombination of electrons injected from an electron injection electrode (cathode) and holes injected from a hole injection electrode (anode) in a light-emitting layer
Data Source
AI summary
An organoelectroluminescent device according to the present invention employs compounds of characteristic structures as a hole transport material and a dopant material in a hole injection layer or a hole transport layer, and in an emissive layer, respectively, and thus can be driven at a low voltage and realize highly efficient emission characteristics with excellent external quantum efficiency. Thus, the organoelectroluminescent device may be industrially advantageously used in a flexible display device, a flexible display device, a single-color or white-color flat lighting device, a single-color or shite-color flexible lighting device, and the like.