Triblock copolymer tunes 1-dimensional AgTCNQ nanostructures in aqueous medium by a one-pot reaction

Metal-organic charge transfer complexes, MTCNQ (M   =   Ag or Cu; while, TCNQ   =   7,7,8, 8-tetracyanoquinodimethane), have received great attentions for their electrical and optical properties. To prepare AgTCNQ, poly(ethylene glycol)-blockpoly(propylene glycol)-block-poly(ethylene glycol) (P123) has been applied as a soft template for the growth of AgTCNQ. This triblock copolymer is the structure directing agent and necessary to the formation of the AgTCNQ nanostructure. By tuning the concentration of P123, we achieved two novel AgTCNQ nanocrystals (nanospindle and nanocones) for the first time via a one-pot reaction in aqueous solution. In addition, sodium citrate acts as a reductant and ensures the proceeding of the reaction between Ag + and TCNQ particles. A ligand-limited facet growth mechanism has been proposed to explain the shape regulation of AgTCNQ through the facet block effect by P123. This soft template method also enlightens us in the synthesis of other organic crystals with different shapes.