Preparation of nano/microstructures of CuOEP-TCNQ cocrystals with controlled stacking and their photoresponse properties

Nano/microstructures of copper octaethylporphyrin (CuOEP, donor)-tetracyanoquinodimethane (TCNQ, acceptor) cocrystals with controlled stacking were prepared by a facile solution method and fully characterized. The as-prepared CuOEP-TCNQ cocrystals were either nanoribbons of TCNQ center dot 2CuOEP or microrods of TCNQ center dot CuOEP, which had DDA(DDA)(n)DDA and DA(DA)(n)DA stacking, respectively. For the first time, a phase transformation was found to occur from nanoribbons of TCNQ center dot 2CuOEP to microrods of TCNQ center dot CuOEP, which was mainly controlled by the concentration of TCNQ. Moreover, prototype devices were fabricated to investigate their photoresponse properties. The results demonstrated that the DDA(DDA)(n)DDA stacking had much better photoresponse than the DA(DA)(n)DA stacking.