Combined experimental and density functional theory studies on novel 9‐(4/3/2‐cyanophenyl)‐9 H ‐carbazole‐3‐carbonitrile compounds for organic electronics

We have synthesized a series of novel hybrid molecules 9‐(2‐cyanophenyl)‐9 H ‐carbazole‐3‐carbonitrile ( o‐ CNCbzCN) , 9‐(3‐cyanophenyl)‐9 H ‐carbazole‐3‐carbonitrile ( m ‐CNCbzCN) and 9‐(4‐cyanophenyl)‐9 H ‐carbazole‐3‐carbonitrile ( p ‐CNCbzCN) , comprising electron‐donating carbazole and electron‐accepting nitrile groups. Three positional isomers were synthesized with a view to tune photophysical and electrochemical properties of the hybrids. The photophysical study displayed absorption maxima in the range of 281–340 nm and 277–298 nm whereas emission maxima in the range of 349–366 nm and 366–369 nm in toluene and dimethylformamide (DMF), respectively. These molecules demonstrated suitable frontier molecular orbital (FMO) energy levels and ensure good thermal and morphological stability. Among these synthesized molecules, m ‐CNCbzCN showed very high decomposition temperature ( T d = 341°C) whereas p ‐CNCbzCN exhibited good glass transition ( T g = 182°C) as well as melting temperature ( T m = 236°C), indicating its significant stability and potential utility as a bipolar host material for efficient phosphorescent organic light‐emitting diodes (PhOLEDs).