Multilayer Organic Light-Emitting Element With Compound LUMO Selection
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Solution Overview
Problem
Existing multilayer organic light emitting elements suffer from high drive voltage, low efficiency, and reduced durability due to electron trapping in intermediate layers, and do not adequately consider the relationship between HOMO and LUMO energy levels of compounds in light emitting layers.
Innovation Solution
An organic light emitting element with a specific arrangement of light emitting units and charge generation layers, where the compounds in the first and second light emitting layers satisfy LUMO(A) > LUMO(B), promoting efficient electron-hole recombination and reducing drive voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an intermediate layer is introduced in multilayer organic light emitting elements, then drive voltage increases and efficiency decreases, but durability improves
Solution Approach 1:
The patent applies parameter changes by carefully selecting and optimizing the energy levels (HOMO and LUMO) of the compounds in the intermediate layer and light emitting layers. By adjusting these energy level parameters to specific ranges and relationships, the patent achieves both low drive voltage and high durability simultaneously, resolving the contradiction between these two parameters.
Solution Approach 2:
The patent uses composite materials by combining multiple organic compounds with specific properties in the intermediate layer and light emitting layers. The intermediate layer comprises compounds with specific HOMO/LUMO energy levels, and the light emitting layers comprise compounds with complementary energy levels, creating a composite structure that achieves both low drive voltage and high durability.
2Device complexity
If light emitting layers are designed without considering HOMO-LUMO energy level relationships, then device complexity is reduced, but drive voltage increases
Solution Approach 1:
The patent systematically optimizes the energy level parameters (HOMO and LUMO) of the compounds used in the device. By establishing specific energy level relationships between the intermediate layer and light emitting layers, the patent achieves low drive voltage while maintaining manageable design complexity through structured parameter selection.
3Ease of manufacture
If electron trapping is allowed in intermediate layers, then manufacturing simplicity is maintained, but efficiency decreases and durability reduces
Solution Approach 1:
The patent changes the energy level parameters of the compounds in the intermediate layer to specific ranges that prevent electron trapping. By selecting compounds with appropriate HOMO and LUMO energy levels, the patent maintains manufacturing simplicity while significantly improving efficiency and durability, eliminating the need for complex additional layers or structures.
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 structure achieves low drive voltage and improved durability by enhancing electron injection and reducing electron trapping, resulting in efficient light emission.
Implementation Method 1
An organic electroluminescence element is an element that emits light when an anode, a cathode, and an organic compound layer that is interposed between these electrodes and includes a light emitting layer are energized
Data Source
AI summary
An organic light emitting element includes a first electrode, a first light emitting unit, a charge generation layer, a second light emitting unit, and a second electrode that are arranged in this order. The second light emitting unit includes a first light emitting layer. The first light emitting unit includes a first organic layer, a second light emitting layer, and a second organic layer arranged in this order of proximity to the first electrode. The first light emitting layer contains a first compound and a second compound. The first organic layer contains a third compound. The second light emitting layer contains a fourth compound. The second organic layer contains a fifth compound. The first compound and the second compound satisfy relationship LUMO(A)>LUMO(B), where LUMO(A) and LUMO(B) respectively represent lowest unoccupied molecular orbital energy levels of the first compound and the second compound.