Precise growth of low-dimensional pyrene·perylene·TCNQ co-crystals and structure–property related optoelectronic properties†
A phase-transformation method has been developed for the precise growth of charge-transfer (CT) co-crystals with varied stoichiometries. Perylene·TCNQ (P1T1) microrods, pyrene·perylene·TCNQ (PyPeT) microrods and (perylene)3·TCNQ (P3T1) microsheets were successfully constructed. The phase transformation can not only happen from P1T1 or P3T to PyPeT, but also from P3T1 to P1T1, which can be controlled by changing the solute concentration. Due to the additional pyrene in PyPeT compared to P1T1, devices based on PyPeT microrods show slightly lower electron mobility and much larger positive threshold than P1T1 microrods. In addition, both of them can be used as phototransistors with a maximum Ion/Ioff ratio of ca. 1000.