Connection position-induced aggregation-diminished and aggregation-enhanced organic room temperature electrophosphorescence†

Abstract

It remains a significant challenge to develop organic room-temperature electrophosphorescence. In this work, we develop two organic phosphors D31 and D32 with acridine as the electron donor, benzophenone with different connection positions as the electron acceptor, and oxygen atom as the bridge. The insertion of the oxygen atom would effectively facilitate the intersystem crossing (ISC) and phosphorescence processes. Due to the different connection positions of benzophenone, D31 and D32-based non-doped devices exhibit an aggregation-diminished and aggregation-enhanced organic room temperature electrophosphorescence with the maximum external quantum efficiency (EQE_max) of 4.51% and 6.70%, respectively. Moreover, the host-free sensitization device based on D32 and S-Cz-BN revealed a significantly boosted EQE_max of 17.11% with a small full-width at half maximum (FWHM) of 28 nm. This work provides a novel approach to develop highly efficient aggregation-induced organic room temperature electrophosphorescence.