The effect of molecular structure on the properties of quinoxaline-based molecules for OLED applications

Abstract Different donor-acceptor-donor (D-A-D) and donor-π-bridge-acceptor-π-bridge-donor (D-π-A-π-D) systems based on quinoxaline acceptor are compared. A significant difference in electrochemical and photophysical properties was found depending on molecular structure. A luminescence shift from 539 nm up to 671 nm was observed upon extension of conjugation length. The studied compounds were tested in fluorescent organic light emitting diodes (OLEDs) demonstrating an external quantum efficiency up to 4.5% for the deep red non-doped device and 7% for the doped into the exciplex host device. A quantum-chemical interpretation of the electroluminescence spectra for the fabricated OLEDs was carried out including modelling of excimers and exciplexes.