OLED Hole Transport Compound for Voltage and Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current hole transport materials in OLED elements face issues such as poor solubility, high voltage due to low mobility, cross-talk between pixels, inadequate electron blocking, and low light-emitting efficiency due to deep LUMO and triplet energy levels.
Innovation Solution
A compound with a shallow HOMO and LUMO energy level, high triplet energy level, appropriate hole mobility, and good thermal stability is developed, which can be used in the hole transport layer, electron blocking layer, or auxiliary light-emitting layer to reduce working voltage and improve light-emitting efficiency and lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a commercially available hole transport layer material is used, then the material is easy to obtain, but the material has poor solubility resulting in poor cleaning effect of evaporation mask
Solution Approach 1:
The patent modifies the molecular structure of hole transport materials by introducing specific substituents (e.g., fluoro, cyano, or other electron-withdrawing groups) at defined positions (R1-R6) to change the solubility parameter while maintaining the hole transport function. This allows the material to achieve both ease of manufacture and proper cleaning effect during evaporation mask removal.
2Device complexity
If a hole transport material with low mobility is used, then the material structure can be simplified, but the overall voltage of the element becomes high
Solution Approach 1:
The patent optimizes the hole mobility parameter by selecting specific molecular structures with appropriate substituents that enhance charge transport capability. The modified structures achieve higher hole mobility without excessive complexity, thereby reducing the overall voltage requirement while maintaining reasonable material structure complexity.
3Speed
If a hole transport material with extremely high mobility is used, then the charge transport performance is improved, but cross-talk between adjacent pixels occurs
Solution Approach 1:
The patent introduces spatially selective substituents at specific positions (R1-R6) in the molecular structure to create local variations in electronic properties. This allows different regions of the material to have optimized characteristics: high mobility in the bulk while maintaining proper confinement to prevent cross-talk between adjacent pixels through localized electronic structure modification.
4Reliability
If a material with deep LUMO energy level is used, then the electron blocking capability is improved, but the light-emitting efficiency decreases due to exciton blocking
Solution Approach 1:
The patent systematically adjusts the LUMO and triplet energy level parameters by modifying substituent groups (R1-R6) and their electronic properties. The optimized structure achieves a balanced energy level configuration where the LUMO is deep enough for effective electron blocking while the triplet energy level is appropriately positioned to avoid exciton blocking, thereby maintaining high light-emitting efficiency.
5Ease of manufacture
If a material with low triplet energy level is used, then the material synthesis is easier, but the light-emitting efficiency is low due to exciton blocking in the light-emitting layer
Solution Approach 1:
The patent modifies the triplet energy level parameter through strategic substitution of groups (R1-R6) with different electronic and steric properties. The optimized structure achieves higher triplet energy levels that prevent exciton blocking in the light-emitting layer while maintaining reasonable synthesis complexity through systematic modification of available chemical building blocks.
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 compound effectively reduces the working voltage, enhances light-emitting efficiency, and extends the lifetime of OLED elements by facilitating hole transport, blocking electrons, and confining excitons within the light-emitting layer.
Implementation Method 1
the compound has a relatively shallow HOMO energy level... appropriate hole mobility... to reduce a working voltage of the element
Implementation Method 2
a LUMO energy level of the material is too deep to effectively block electrons that might migrate beyond the light-emitting layer
Implementation Method 3
a triplet energy level of the material is too low to effectively block excitons in the light-emitting layer, resulting in low light-emitting efficiency
Data Source
AI summary
Provided are a compound, an organic light-emitting element including the same, a display panel and a display device. The compound has a structure represented by Formula I. The organic light-emitting element includes an anode, a cathode and an organic thin film layer disposed between the anode and the cathode; where the organic thin film layer includes a light-emitting layer, and further includes any one or a combination of at least two of a hole transport layer, an electron blocking layer and an auxiliary light-emitting layer, and at least one of the hole transport layer, the electron blocking layer and the auxiliary light-emitting layer contains at least one of the compounds. The compound has a relatively shallow HOMO energy level, a relatively shallow LUMO energy level, a relatively high triplet energy level, an appropriate hole mobility, a relatively high Tg, a large molecular torque and good thermal stability.