Photopolymerization studies of a light-emitting liquid crystal with methacrylate reactive groups for electroluminescence

摘要

Light-emitting reactive mesogens are promising materials for photolithographically processable organic light-emitting diodes (OLEDs). We study the photopolymerization of a fluorene-based mesogen with methacrylate photoreactive groups. We find that there is no significant change in the photoluminescence quantum efficiency when the mesogen is photopolymerized in a glovebox with oxygen and water concentration at < 20 parts per million. There is significant quenching of luminescence when the photopolymerization is carried out in a less controlled environment. A real-time measurement is used to monitor changes in the FTIR spectrum of the compound during polymerization. No photo-initiator is added to the mesogen suggesting that the photopolymerization is self-initiated by the chromophore. We show that the self-initiation does not proceed by fragmentation of the aromatic core and suggest an alternative mechanism.