Thermally Activated Delayed Fluorescence (Green) in Undoped Film and Exciplex Emission (Blue) in Acridone–Carbazole Derivatives for OLEDs (original) (raw)

Donor-acceptor-donor (DAD) materials (1,2) having acridone as acceptor unit and carbazole as donor were synthesized for opto-electronic applications. Carbazole was substituted on 2,7 positions of acridone in 1, while, 3,6-trifluoromethylphenyl carbazole was substituted in 2. Steady state and time dependent emission properties of these compounds were studied in detail to get insight on their possible thermally activated delayed fluorescence (TADF) behaviour. The singlet-triplet energy gap (∆E ST) was found to be as low as 0.17 eV (1) and 0.15 eV (2), favourable for TADF materials. Both these materials were found to be efficient green TADF emitters in organic light emitting diode (OLED) devices.