3,12-Dimethoxy-7,8-dicyano-[5]helicene as a novel emissive material for organic light-emitting diode

3,12-Dimethoxy-7,8-dicyano-[5]helicene (DDH) was introduced as a novel emissive material for organic light-emitting diode. It shown good thermal stability and no glass transition temperature was observed. The LUMO, HOMO and energy band gap (?3.3, ?5.9 and 2.6 eV) of this compound were determined using cyclic voltammetry technique. Fluorescence quantum yield of DDH in chloroform is 0.27. The turn-on voltage of OLEDs with a configuration of ITO/PEDOT:PSS/DDH/Ca/Al was not a function of DDH thickness in a range of 60–100 nm. The best OLED, in which DDH thickness was 100 nm, exhibited a turn-on voltage of 3.7 V with maximum brightness of 1587 cd/m² at 8.0 V and 281 mA/cm². The maximum current efficiency and power efficiency were 0.64 cd/A and 0.29 lm/W, respectively. The CIE coordinates of the OLED electroluminescence, however, appeared to depend on the applied voltage as they were (0.38,0.47) at 5.0 V and (0.51,0.44) at 8.0 V.