OLED Light Emission Orientation via Energy Level Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The simple addition of a delayed fluorescent material to the light emitting layer of a two-component organic electroluminescent device does not directly result in good light emission capability, leading to suboptimal performance of light emitting materials.
Innovation Solution
Enhancing the orientation of the light emitting material in the light emitting layer by selecting a delayed fluorescent material that satisfies specific energy relationships with other organic compounds, including a first organic compound, a second organic compound, and a third organic compound, as defined by certain energy and S-value conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a delayed fluorescent material is simply added to the light emitting layer of a two-component organic electroluminescent device, then the device structure is enhanced to utilize triplet states, but the light emission capability deteriorates due to poor orientation and suboptimal performance of light emitting materials
Solution Approach 1:
The patent applies parameter changes by optimizing the energy level relationships between the delayed fluorescent material (second organic compound) and other compounds in the light emitting layer. Specifically, it establishes that ES1(1) > ES1(2) > ES1(3) and controls the S value relationship S(1,2,3) < S(1,3), where ES1 represents lowest excited singlet energy and S represents orientation parameter. These parameter optimizations enable both high light emission efficiency through triplet state utilization and maintained light emission capability through proper material selection and orientation control.
2Use of energy by moving object
If a delayed fluorescent material is added to improve emission efficiency by utilizing triplet states, then energy utilization is improved, but the orientation and performance of the light emitting material deteriorates
Solution Approach 1:
The patent changes the energy level parameters and orientation parameters of the light emitting layer components. It specifies that the delayed fluorescent material should have ES1(2) between ES1(1) and ES1(3), and S(1,2,3) smaller than S(1,3) by 0.03 or more. These parameter specifications ensure that the light emitting material maintains proper orientation (improved manufacturing precision) while the delayed fluorescent material enables triplet state utilization (improved energy use).
Solution Approach 2:
The patent creates a composite three-component light emitting layer combining a host material (first organic compound), a delayed fluorescent material (second organic compound), and a light emitting material (third organic compound). This composite structure allows the delayed fluorescent material to enhance energy utilization through reverse intersystem crossing while the host and light emitting materials maintain proper orientation and performance through the specified energy and S value relationships.
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
This approach significantly enhances the light emission characteristics of the organic light emitting device, achieving higher orientation and efficiency of the light emitting material in the presence of a delayed fluorescent material.
Implementation Method 1
A delayed fluorescent material is a material which, in an excited state, after having undergone reverse intersystem crossing from an excited triplet state to an excited singlet state, emits fluorescence when returning back from the excited singlet state to a ground state thereof
Implementation Method 2
emits fluorescence when returning back from the excited singlet state to a ground state thereof
Data Source
AI summary
An organic light emitting device including a light emitting layer containing a first organic compound, a second organic compound as a delayed fluorescent material, and a third organic compound, having lowest excited singlet energy ES1 satisfying ES1(1)>ES1(2)>ES1(3). The S value of the light emitting layer is smaller than the S value of the reference light emitting layer containing other light emitting layer components than the second organic compound.