OLED Exciton Barrier Layer Host Material Selection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic light-emitting diode (OLED) array substrates face challenges in achieving high light emitting efficiency due to the restrictive relaxation of triplet state excitons, which reduces overall light output, and the complexity and cost of adding an exciton barrier layer in the manufacturing process.
Innovation Solution
Incorporating an exciton barrier layer between the anode and light-emitting layer, made from a host material with the maximum highest occupied molecular orbital (HOMO) energy level, which blocks triplet state excitons and increases light emitting efficiency without the need for additional vapor deposition devices, thereby simplifying the preparation process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an exciton barrier layer is added to block triplet state excitons and increase light emitting efficiency, then light emitting efficiency is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The exciton barrier layer is formed using the same host material from one of the light-emitting layers, allowing a single vapor deposition device to produce multiple layers with different functions. The host material serves both as the light-emitting layer material and the exciton barrier layer material, eliminating the need for additional specialized equipment while achieving triplet state exciton blocking to improve light emitting efficiency.
Solution Approach 2:
The patent controls the formation of the exciton barrier layer by adjusting deposition parameters such as deposition rate and thickness during the vapor deposition process. By changing these parameters, the same host material can form layers with different properties - one that emits light and another that blocks triplet state excitons - using the same equipment, thus improving efficiency without increasing device complexity.
2Loss of energy
If an exciton barrier layer is added to block triplet state excitons and increase light emitting efficiency, then light emitting efficiency is improved, but manufacturing cost increases
Solution Approach 1:
The exciton barrier layer is formed using the same host material from one of the light-emitting layers, allowing a single vapor deposition device to produce multiple layers with different functions. The host material serves both as the light-emitting layer material and the exciton barrier layer material, eliminating the need for additional specialized equipment while achieving triplet state exciton blocking to improve light emitting efficiency.
Solution Approach 2:
The vapor deposition device forms both the light-emitting layers and the exciton barrier layers using the same host material source. The process utilizes the material and equipment already present in the system, avoiding the need for separate material preparation and additional deposition equipment, thereby reducing manufacturing cost while improving light emitting efficiency through effective triplet state exciton blocking.
3Loss of energy
If different host materials are used for different light-emitting layers to achieve different colors, then light emitting efficiency is improved, but the preparation process becomes more complex
Solution Approach 1:
The patent selects one host material from among the different host materials used in various light-emitting layers to form the exciton barrier layer. This allows the same vapor deposition device and material source to be used for both light-emitting layer deposition and exciton barrier layer formation, simplifying the preparation process while maintaining the benefits of different host materials for different colors in the light-emitting layers.
Solution Approach 2:
The patent combines the formation of light-emitting layers with different host materials and the exciton barrier layer formation into a single integrated vapor deposition process. By selecting one of the existing host materials for the barrier layer, the process merges multiple deposition steps into one continuous operation, reducing preparation complexity while preserving the color-specific optimization achieved through different host materials.
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 implementation of the exciton barrier layer enhances light emitting efficiency by increasing the quenching of triplet state excitons and allows for the adjustment of light wavelength by varying the thickness of the exciton barrier layer, resulting in improved brightness and reduced manufacturing complexity and costs.
Implementation Method 1
The implementation of the exciton barrier layer enhances light emitting efficiency by increasing the quenching of triplet state excitons
Implementation Method 2
The forming material of the exciton barrier layer comprises a host material of one light-emitting layer that has a maximum highest occupied molecular orbital (HOMO) energy level amongst the host materials of all light-emitting layers
Data Source
AI summary
An organic light-emitting diode (OLED) array substrate and a display apparatus are disclosed. The OLED array substrate includes a plurality of OLEDs. The OLED includes an anode, a light-emitting layer and a cathode which are provided in this order, and further includes an exciton barrier layer which is arranged between the anode and the light-emitting layer and is in contact with the light-emitting layer. A forming material of the light-emitting layer includes a host material and a guest material which is doped in the host material, and the light-emitting layers of the OLEDs are configured for emitting light of a plurality of colors. A forming material of the exciton barrier layer includes a host material of one light-emitting layer that has a maximum highest occupied molecular orbital energy level amongst the host materials of all light-emitting layers.