Acridan Ring Compounds for OLED Hole Transport and Electron Blocking
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Solution Overview
Problem
Current organic electroluminescent devices face limitations in achieving high luminous efficiency, low driving voltage, and durability due to insufficient hole injectability, electron blocking performance, heat resistance, and amorphousness in existing hole transport materials.
Innovation Solution
Development of compounds with a substituted acridan ring structure that exhibit enhanced hole injectability, electron blocking ability, and thermal stability, used in the hole injection, transport, or electron blocking layers to improve the efficiency and durability of organic electroluminescent devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If NPD is used as hole transport material, then hole transportability is improved, but heat resistance deteriorates due to low glass transition point causing crystallization
Solution Approach 1:
The patent develops compound (1) as a composite molecular structure combining acridan ring core with specific substituent groups (Ar1, Ar2, Ar3) that work synergistically to achieve both high hole mobility and superior thermal stability, resolving the contradiction between transportability and heat resistance
Solution Approach 2:
The patent systematically varies the glass transition temperature parameter by modifying the substituent groups on the acridan ring, achieving compounds with Tg of 100°C or higher while maintaining adequate hole mobility, thus changing the material parameter to resolve the contradiction
2Speed
If aromatic amine derivatives with high hole mobility are used, then hole transportability is improved, but electron blocking performance deteriorates
Solution Approach 1:
The patent applies local quality by designing the acridan ring structure with specific electron-deficient characteristics in certain regions (the ring system itself) while maintaining electron-rich substituents in other regions, creating localized electron blocking capability without compromising overall hole mobility
Solution Approach 2:
The compound (1) represents a composite design where the acridan core provides electron blocking functionality while the aromatic substituents (Ar1, Ar2, Ar3) provide hole transport pathways, achieving both functions simultaneously
3Ease of manufacture
If materials with low heat resistance are used, then ease of manufacture is improved, but device lifetime deteriorates due to thermal decomposition
Solution Approach 1:
The patent changes the thermal stability parameter by designing compounds with glass transition temperatures of 100°C or higher, preventing thermal decomposition during device operation while maintaining ease of deposition through vacuum evaporation or solution processing
4Ease of manufacture
If materials with low amorphousness are used, then ease of manufacture is improved, but device lifetime deteriorates due to crystallization of thin film
Solution Approach 1:
The patent systematically increases the glass transition temperature parameter to 100°C or higher, which kinetically suppresses crystallization of the thin film during device operation while allowing simple deposition processes to be used
Data Source
AI summary
An organic compound with characteristics excelling in hole-injecting/transporting performance and having an electron blocking ability, a highly stable thin-film state, and excellent heat resistance is provided as material for an organic electroluminescent device of high efficiency and high durability, and the organic electroluminescent device of high efficiency and high durability is provided using this compound. The compound of a general formula (Chemical Formula 1) having a substituted acridan ring structure is used as a constituent material of at least one organic layer in the organic electroluminescent device that includes a pair of electrodes and one or more organic layers sandwiched between the pair of electrodes.