A highly luminescent organic crystal with the well-balanced charge transport property: The role of cyano-substitution in the terminal phenyl unit of distyrylbenzene

• Cyano-substituted on terminal phenyl units of distyrylbenzene crystal was prepared.
• The crystal (2-CSB) presents a high luminescence efficiency of ∼55%.
• The crystal hole and electron mobilities are 0.66 and 0.29 cm2/Vs, respectively.
• Intermolecular C–H…N interactions induce a face-to-face slipped π stacking motif.

1,4-bis(2-cyano styryl)benzene (2-CSB) crystal with cyano substituent groups introduced to the terminal phenyl rings of distyrylbenzene (DSB) has been prepared and its luminescence efficiency could be as high as ∼55%. Based on the analyses of cyclic voltammetry and crystal structure, cyano substituents not only lower the LUMO level but also result in a change of the packing mode from the herringbone arrangement to the face-to-face slipped π stacking motif. Then field-effect transistors (FETs) based on high-quality 2-CSB crystals grown by the physical vapor transport method have been fabricated and the highest hole and electron mobilities were measured as 0.66 and 0.29 cm2/Vs, which enhanced the corresponding values of DSB crystal by up to one and two orders of magnitude, respectively. 2-CSB crystal simultaneously combined the high luminescence and the well-balanced mobility is expected to be of interest for the fundamental research of organic light-emitting devices.

Cyano substituted distyrylbenzene derivative (2-CSB) crystal has the high luminescence efficiency of ∼55% and well-balanced charge transport characteristics with the hole and electron mobility of 0.66 and 0.29 cm2/Vs, respectively. The introduction of cyano substituents lowers the LUMO level and is efficient to electron injection into 2-CSB. Meanwhile, intermolecular C–H⋯N interactions construct the face-to-face slipped π stacking motif facilitating carrier transport.Figure optionsDownload as PowerPoint slide