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 3.7V with maximum brightness of 1587 cd/m(2) at 8.0 V and 281 mA/cm(2). The maximum current efficiency and power efficiency were 0.64 cd/A and 0.291m/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. (C) 2010 Elsevier B.V. All rights reserved.