On-chip screening of experimental conditions for the synthesis of noble-metal nanostructures with different morphologies.

The applications of nanostructures critically depend on their morphologies. Although significant progress has been made in the chemical synthesis of nanostructures with a variety of different morphologies, it is still highly desired to develop an approach that allows one to quickly identify the best set of parameters for nanostructure syntheses. Herein, an on-chip approach to the rapid screening of experimental conditions pivotal to the production of nanostructures with different morphologies is reported. The key component of this approach is an array of reactors containing solutions with a one- or two-dimensional gradient in reagent concentration, pH value, or reaction temperature. In the proof-of-concept experiments, the parameters needed for the production of Au and Pd nanostructures with various morphologies are quickly identified. In principle, this approach can be extended to other systems for rapid screening and optimization of experimental conditions involved in the syntheses of different types of nanostructures.