Xanthene-based phosphine oxide host with the planar multi-insulating structure for efficient electrophosphorescence

A phosphine oxide (PO) host containing planar xanthene (XantPO) was chosen to investigate the influence of the structure of chromophores on the properties of the host. Owing to the multi-insulating linkages, the planar structure of XantPO also realizes high first triplet excited level (T1) of 2.92 eV, and supports excellent morphological and thermal stability with the high temperature of glass transition (Tg, 135 °C) and temperature of decomposition (Td, 369 °C). On the basis of theoretical simulation and electrochemical analysis and bright and efficient green and blue phosphorescent organic light-emitting diodes (PHOLEDs) of XantPO, it indicated that the configuration of chromophores in hosts can remarkably influence the device performance even if their optical properties were very approximate.

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► XantPO with planar xanthene was chosen as a host for electrophosphorescence.
► The influence of chromophores’ structures on the host properties is investigated.
► The optical properties of the hosts studied were very approximate.
► However, the device performance was still remarkably influenced.
► This is attributed to the different electrical properties from changed configuration.