Triphenylene fused ring hosts for OLED energy stability
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Solution Overview
Problem
Current organic light emitting devices (OLEDs) face challenges in achieving high efficiency and stability, particularly in accommodating red, green, and blue phosphorescent dopants without energy quenching, and in balancing charge transport for improved device performance.
Innovation Solution
Compounds comprising a triphenylene moiety and benzo- or dibenzo-furan, benzo- or dibenzo-thiophene, or benzo- or dibenzo-selenophene moieties with fused substituents are used as hosts in OLEDs, which provide high triplet energy and efficient charge balance, accommodating various phosphorescent emitters and enhancing device stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional host materials are used in OLEDs, then device fabrication is simpler, but energy quenching occurs when accommodating red, green, and blue phosphorescent dopants
Solution Approach 1:
The patent modifies the host material structure by incorporating triphenylene core with benzofuran, benzothiophene, or benzoselenophene moieties and fused ring substituents. This structural parameter change increases triplet energy levels to prevent energy quenching when accommodating red, green, and blue phosphorescent dopants with different energy requirements.
Solution Approach 2:
The host material combines multiple functional moieties (triphenylene core, benzofuran/benzothiophene/benzoselenophene units, and fused ring substituents) into a composite molecular structure. This composite approach allows simultaneous achievement of high triplet energy for energy stability and appropriate charge transport properties.
2Reliability
If host materials with high triplet energy are used to prevent energy quenching, then phosphorescent dopant accommodation improves, but charge transport balance deteriorates
Solution Approach 1:
The host material employs different substituents with specific local properties: electron-donating groups (alkyl, alkoxy, amino) and electron-withdrawing groups (cyano, carbonyl) are strategically placed on the triphenylene core. This local quality differentiation enables simultaneous optimization of charge transport balance and triplet energy levels for stable phosphorescent dopant accommodation.
Solution Approach 2:
The patent systematically varies substituent types, positions, and combinations on the host molecule to independently tune charge transport parameters while maintaining high triplet energy. This parameter optimization allows the host to simultaneously support balanced charge injection and prevent energy quenching.
3Productivity
If substituents are added to enhance charge transport, then device performance improves, but manufacturing complexity increases
Solution Approach 1:
The host material is designed as modular segments: a triphenylene core unit, benzofuran/benzothiophene/benzoselenophene bridging units, and various substituent groups. This segmentation allows systematic assembly through well-established coupling reactions, improving manufacturability despite enhanced functionality.
Solution Approach 2:
The triphenylene-based host structure serves multiple functions simultaneously: providing high triplet energy for energy stability, enabling charge transport through substituted groups, and offering structural rigidity for device stability. This multi-functionality reduces the need for separate materials, simplifying the overall device architecture despite complex molecular structure.
Data Source
AI summary
Compounds comprising a triphenylene moiety and a benzo- or dibenzo-moiety are provided. In particular, the benzo- or dibenzo-moiety has a fused substituent. These compounds may be used in organic light emitting devices, particularly in combination with yellow, orange and red emitters, to provide devices with improved properties.