Synthesis of Nanocomposite Materials Using the Reprecipitation Method

Room temperature solution-based synthetic methods are an important option for the production of a wide range of nanomaterials. These methods often rely on self-assembly or self-organization of molecular precursors, with specific control of their nucleation and growth properties. We are developing strategies for the creation of multifunctional composite nanoparticles as well as models for predicting the bulk properties from the individual components and parameters of the processing conditions. One method of synthesis is a reprecipitation technique in which nanoparticle nucleation and growth is induced by the rapid injection of a molecular solution into a miscible non-solvent. Here we demonstrate that this method can be extended to multiple components, enabling the preparation of nanoparticles with multiple functionalities as well as materials with new properties arising from cooperative effects between the constituents. We synthesized nanocrystals of the charge transfer complex perylene:TCNQ (tetracyanoquinodimethane). Using the increase of the charge transfer band in the near infrared and dynamic light scattering data we try to develop a model for the formation and growth of these nanocrystals. By freeze drying the samples during growth and imaging with scanning electron microscope, we observe the morphologies of the crystals during their growth.