Highlights

Nanoparticle Design and Metamaterials

Scientific Achievement

We are working on development of reliable and controllable method to form periodic superlattices consisting of several components.  We are trying different approaches to achieve this goal including direct self-assembly, Lanmuir-Blodget and templated self-assembly. Access to the electron microscopes is very important for our project.  This project is performed at CNM where there is not in house TEM, so we rely on Microscopy Center.  Transmission electron microscope Phillips CM30 was used to perform the characterization of the size and size distribution of the nanocrystal building blocks.  In our field (material science) TEM is an instruments that is used on daily basis. I used electron diffraction to determine the crystalline structure of nanoparticles.  Also we use this tool to monitor the self-assembled periodic superlattices.  We synthesized individual building blocks and selected the samples (about 18) with the narrowest size and shape distribution by TEM for further work.  Also we started self-assembly part of the project.

Significance

Control over self-assembly is very important from scientific and practice point of views and to the best of our knowledge to date there is no successful allowing to create different periodic structures on desired structures  with reasonable degree of control over the structures, periodicity and  dimensions.  This limits the progress in studies of energy and electron transfer in nanoscale single and multicomponent structures that are expected to be interested for solar cells and transistor applications as well as catalysis.  This direction is highly recognized by our community.  Our previous publications on self-assembly have about 50-220 citation in ~2years. The results of our activity were presentated as invited talks at 2 conferences: “Nanoparticle building blocks and their periodic structures,” ACS, New Orleans, LA, Apr. 6-10th, 2008; “Design of matter at nanoscale,” Gordon Research Conference on Environmental Bioinorganic Chemistry, Waterville Valley, NH, June15-20, 2008.

The results obtained with the help of Microscopy Centre were not published yet. However, they provided a good start for out further activity.  Our Distinguished Argonne Postdoctoral Fellow joined the project in August and he keeps making a progress on controllable self-assembly. Also another postdoc in our group is working on the design of multifunctional individual nanoparticles that will allow us to spread the limits of the number of functional components within single nanoparticle superlattices.  We are planning to work on control of self-assembly using Langmuir-Blodget, self-assembly of multi-component nanoparticles and differently shaped nanoparticles.  The optical and electronic properties will be studied at CNM.

Performers

E. Shevchenko, P. Podsiadlo (Argonne-CNM)