Light-Emitting Element Host Material Singlet Triplet Energy Gap
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Solution Overview
Problem
Current light-emitting elements with phosphorescent compounds face challenges in reducing driving voltage and achieving high light emission efficiency, particularly for blue light emission, due to the energy difference between singlet and triplet excited states, and inefficient energy transfer in thermally activated delayed fluorescent emitters.
Innovation Solution
A light-emitting element is designed with a host material and a guest material, where the host material forms an excited complex with a small energy difference between singlet and triplet excitation levels, facilitating efficient conversion of triplet excitons to singlet excitons and energy transfer to a fluorescent compound for enhanced light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phosphorescent compounds are used to convert triplet excited state into light emission, then light emission efficiency is improved, but driving voltage increases due to large energy difference between singlet and triplet excited states
Solution Approach 1:
The patent changes the energy level parameters of the host material by selecting materials with small energy differences between singlet and triplet excited states. This parameter optimization allows efficient triplet-to-singlet conversion while maintaining lower driving voltages, resolving the contradiction between high light emission efficiency and low power consumption.
Solution Approach 2:
The host material acts as an intermediary between the phosphorescent compound and the electrodes. It facilitates energy transfer from triplet excited states to singlet excited states through its specific energy level structure, enabling efficient light emission while reducing the voltage required for excitation.
2Productivity
If thermally activated delayed fluorescent emitters are used, then triplet excitons can be converted to singlet excitons, but energy transfer efficiency is insufficient
Solution Approach 1:
The patent optimizes the energy level parameters of the host material to achieve small energy differences between singlet and triplet states. This enables resonant energy transfer and minimizes energy loss during triplet-to-singlet conversion, significantly improving both conversion efficiency and energy transfer 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 approach results in a light-emitting element with improved light emission efficiency and reduced driving voltage, achieving high fluorescence quantum yield and low power consumption.
Implementation Method 1
a light-emitting element in which a triplet exciton is converted into a singlet exciton and light can be emitted from a compound containing the singlet exciton
Implementation Method 2
efficient energy transfer from a singlet excited state of the host material to a singlet excited state of the fluorescent compound
Implementation Method 3
research and development have been extensively conducted on light-emitting elements using electroluminescence (EL). By application of a voltage between the electrodes of this element, light emission from the light-emitting substance can be obtained.
Data Source
AI summary
A light-emitting element containing a light-emitting material and having high light emission efficiency is provided. The light-emitting element includes a host material and a guest material. The host material includes at least a first molecule and a second molecule having the same molecular structure. The guest material has a function of exhibiting fluorescence or converting triplet excitation energy into light emission. The first molecule and the second molecule each include a first skeleton, a second skeleton, and a third skeleton, and the first skeleton and the second skeleton are bonded to each other through the third skeleton. The first skeleton includes at least one of a π-electron rich heteroaromatic skeleton and an aromatic amine skeleton and the second skeleton includes a π-electron deficient heteroaromatic skeleton. The first molecule and the second molecule have a function of forming an excited complex.