Synthesis of triphenylamine based polysiloxane as a blue phosphorescent host

In this work, a triphenylamine based polysiloxane (PTPAMSi) has been successfully synthesized. The PTPAMSi exhibits a high decomposition temperature (Td = 377 °C) and glass transition temperature (Tg = 63 °C). It also displays good film-forming ability, high morphological stability and good miscibility with the dopant FIrpic as revealed by atomic force microscopy (AFM). The silicon–oxygen linkage of PTPAMSi disrupts its conjugation and results in a sufficiently high triplet energy level (ET = 2.9 eV). A FIrpic-based device using PTPAMSi as a host shows a turn-on voltage of 6.8 V, a maximum external quantum efficiency of 3.8%, and a maximum current efficiency of 7.6 cd A−1. These results demonstrate that using polysiloxane to modify triphenylamine is a promising approach to improve the physical properties of triphenylamine while maintaining its photophysical and electrochemical properties.