Organic Light-Emitting Element Delayed Fluorescent Material Stability
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Solution Overview
Problem
Existing organic light-emitting elements, particularly those using delayed fluorescent materials, face challenges in durability due to instability and limited durability of the organic compounds, which affects their luminescence efficiency and operational lifetime.
Innovation Solution
An organic light-emitting element is designed with a light-emitting layer comprising a first organic compound, a second organic compound with lower lowest excited singlet energy as a delayed fluorescent material, and a third organic compound, where at least one of the compounds has an exposed surface area of a single bond of 91 or more, enhancing the durability and luminescence efficiency by stabilizing the energy transfer process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a delayed fluorescent material is used to improve luminescence efficiency, then the luminescence efficiency is improved, but the durability and stability of the organic light-emitting element deteriorate
Solution Approach 1:
The patent changes the molecular structure parameters of the delayed fluorescent material by introducing specific substituents (such as fluorine atoms, methyl groups, or bulky aromatic groups) to increase the exposed surface area of single bonds to 91 or more. This structural modification maintains the delayed fluorescent properties while significantly improving durability and stability.
Solution Approach 2:
The patent creates a composite organic compound that combines the delayed fluorescent material with stabilizing structural elements. The composite structure integrates the luminescence function with enhanced stability, achieving both high luminescence efficiency and improved durability through the synergistic effect of different structural components.
2Loss of energy
If a delayed fluorescent material is used to improve luminescence efficiency, then the luminescence efficiency is improved, but the operational lifetime of the organic light-emitting element deteriorates
Solution Approach 1:
The patent modifies the molecular parameters of the delayed fluorescent material by increasing the exposed surface area of single bonds through specific structural design. This parameter change reduces molecular degradation during operation, thereby extending the operational lifetime while preserving high luminescence efficiency.
Solution Approach 2:
The patent incorporates stabilizing structural features (such as bulky substituents or rigid frameworks) into the delayed fluorescent material design before the element is operated. This preliminary structural reinforcement prevents degradation during operation, ensuring both high luminescence efficiency and extended operational lifetime.
3Loss of energy
If organic compounds with high energy transfer capability are used to improve luminescence efficiency, then the luminescence efficiency is improved, but the stability of the organic compounds deteriorates
Solution Approach 1:
The patent changes the structural parameters of the organic compounds by designing molecules with specific exposed surface areas of single bonds (91 or more). This structural parameter optimization allows efficient energy transfer while simultaneously enhancing the stability of the organic compound composition during operation.
Solution Approach 2:
The patent introduces a structurally stabilized delayed fluorescent material as an intermediary between the host material and the light-emitting dopant. This intermediary compound facilitates efficient energy transfer while its enhanced structural stability protects the overall system from degradation, maintaining both energy transfer capability and compositional stability.
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 significantly improves the durability and luminescence efficiency of the organic light-emitting element by ensuring high energy stability and reducing degradation, leading to a longer operational lifetime and enhanced performance.
Implementation Method 1
the second organic compound, which is a delayed fluorescent material, plays a role in converting a lowest excited triplet exciton in an organic layer into a higher singlet exciton
Implementation Method 2
a first organic compound, a second organic compound that has lower lowest excited singlet energy than the first organic compound and is a delayed fluorescent material, and a third organic compound that is a light-emitting material with lower lowest excited singlet energy than the second organic compound
Data Source
AI summary
An organic light-emitting element including a first electrode, a second electrode, and a light-emitting layer located between the first electrode and the second electrode. The light-emitting layer contains a first organic compound material, a second organic compound that is a delayed fluorescent material, and a third organic compound that is a light-emitting material. In the second organic compound, an electron is transferred from a plurality of occupied molecular orbitals (OMO) to a lowest unoccupied molecular orbital (LUMO) in a second excited triplet state.