Nanoparticles

Novel Theory Developed by Giannis Mpourmpakis Explains How Metal Nanoparticles Form

  • By Aude Marjolin
  • 12 July 2017

Although scientists have for decades been able to synthesize nanoparticles in the lab, the process is mostly trial and error, and how the formation actually takes place is obscure. However, a study recently published in Nature Communications entitled "“Thermodynamic Stability of Ligand-Protected Metal Nanoclusters” by Giannis Mpourmpakis and PhD candidate Michael G. Taylor explains how metal nanoparticles form. The research, completed in Mpourmpakis’ Computer-Aided Nano and Energy Lab (C.A.N.E.LA.), is funded through a National Science Foundation CAREER award and bridges previous research focused on designing nanoparticles for catalytic applications.

Giannis Mpourmpakis Receives NSF CAREER Award

  • By Aude Marjolin
  • 1 March 2017

Giannis Mpourmpakis' proposal "Designing synthesizable, ligand-protected bimetallic nanoparticles and modernizing engineering curriculum through computational nanoscience " was recently selected for an NSF CAREER award. 

Although scientists can chemically synthesize metal nanoparticles (NPs) of different shapes and sizes, understanding of NP growth mechanisms affecting their final morphology and associated properties is limited. With the potential for NPs to impact fields from energy to medicine and the environment, determining with computer simulations the NP growth mechanisms and morphologies that can be synthesized in the lab is critical to advance NP application. 
Because this is a relatively new field, traditional core courses in science and engineering lack examples from the nanotechnology arena. In addition to improving the research, the award will enable Giannis Mpourmpakis and his students to modernize the traditional course of Chemical Thermodynamics by introducing animation material based on cutting-edge nanotechnology examples, and developing a nanoscale-inspired interactive computer game.

Giannis Mpourmpakis Awarded $550,000 in NSF Funding to Design Metal Nanoparticles That Capture Carbon Dioxide

  • By Aude Marjolin
  • 8 August 2016

Building upon their previous research, Giannis Mpourmpakis and collaborators at Pitt and CMU were awarded grants from the National Science Foundation to develop a novel computational framework that can custom design nanoparticles. In particular, the group is investigating bimetallic nanoparticles to more effectively control their adsorption properties for capturing carbon dioxide from the atmosphere.

The three-year grant, “Collaborative Research: Design of Optimal Bimetallic Nanoparticles,” is led by Giannis Mpourmpakis, with Götz Veser, professor of chemical and petroleum engineering at Pitt and Chrysanthos Gounaris, assistant professor of chemical engineering at Carnegie Mellon University as co-investigators. The NSF Division of Civil, Mechanical and Manufacturing Innovation (CMMI) awarded $350,395 to Pitt and $199,605 to CMU to support computational research and targeted experiments.

Karl Johnson and Jill Millstone Awarded 1.5 M Grant to Identify and Destroy Hazardous Chemicals

  • By Aude Marjolin
  • 8 August 2016

Karl Johnson and Jill Millstone will collaborate with Pitt chemistry professor Nathaniel Rosi and Temple chemistry professor Eric Borguet on research funded by a grant from the Defense Threat Reduction Agency's (DTRA) Joint Science and Technology Office (JSTO) within the United States Department of Defense. They will investigate the use of multifunctional metal-organic frameworks (MOFs) with plasmonic cores that can be used to detect and destroy chemical warfare agents and toxic industrial chemicals. The $1.5 M award comes with a 1 M dollar 2 year option period after the initial 3 years. The collaborative team will develop and study new MOF-nanoparticle hybrid materials for the selective detection and destruction of toxic chemicals.

Department of Chemistry, University of Pittsburgh
Ph.D., Northwestern University, 2008
Summary:

Inorganic and Materials Chemistry; Nanomaterials; Mechanochemistry; Surface and Colloid Chemistry

Whether they will be used in catalysis or artificial limbs, nanoparticle surfaces influence every aspect of their behavior. The ligand shell of a nanocrystal can determine its luminescence, its performance in a solar cell, or its clearance from the human body – to name just a few examples. In the Millstone group, we are interested in synthetically controlling this nanoparticle surface architecture – both the crystallographic and chemical composition – in order to develop new nanoparticle morphologies and reaction mechanisms that will have applications in fields ranging from catalysis to medicine.

Colloidal Nanoparticle Alloys: From bronze to steel, alloyed materials have defined the technological capabilities of their times, and like their monometallic counterparts, can experience dramatic changes in their physical properties at the nanoscale. Small, multimetallic nanoparticles (diameter = 1-5 nm) promise to provide improved catalysts for efficient use of fossil fuel resources as well as multifunctional tools in biomedical applications. However, current methods to prepare discrete, multimetallic particles afford limited tunability of particle composition, especially with respect to selectivity between alloyed, core-shell and Janus architectures. We use particle surface chemistry to control nanoparticle composition and elucidate both the synthesis and the resulting materials using a wide variety of electron microscopy and molecular characterization techniques. 

Multifunctional Nanoparticle Synthesis:  It is well known that the physical properties of nanoscale materials are highly dependent on their morphology. However, there is currently no systematic way to design and then rationally access a particular nanoparticle architecture. Elucidating these pathways would allow us to better use our current materials, and more effectively tailor new ones. Just as organic chemistry research has developed a mechanistic framework and synthetic toolbox that has produced everything from plastics to pharmaceuticals, so too must these concepts be developed for nanochemistry in order to harness the similar potential of nanomaterials. Through the discovery of nanoparticle reaction mechanisms, we work to develop a set of physical, analytical, and synthetic principles to rationally generate complex, highly-tailored nanoparticles for environmental remediation and catalysis applications.

Mechanochemistry of nanoparticles: At the nanoscale, the interplay between mechanical forces and physical properties is likely exaggerated compared to bulk materials. We are interested in understanding how mechanical forces can be used to manipulate the chemical reactivity of nanostructures. We will work to understand the response of anisotropic nanoparticles to mechanical stresses, and establish how mechanical perturbation can be used as a new type of synthetic tool in the development and application of nanomaterials.

Most Cited Publications: 
  1. "Observation of a quadrupole plasmon mode for a colloidal solution of gold nanoprisms," Jill E. Millstone, Sungho Park, Kevin L. Shuford, Lidong Qin, George C. Schatz, and Chad A. Mirkin, J. Am. Chem. Soc. 127, 5312 (2005)
  2. "Rationally designed nanostructures for surface-enhanced Raman spectroscopy," Matthew J. Banholzer, Jill E. Millstone, Lidong Qin and Chad A. Mirkin, Chem. Soc. Rev. 37, 885 (2008)
  3. "Colloidal gold and silver triangular nanoprisms," Jill E. Millstone, Sarah J. Hurst, Gabriella S. Métraux, Joshua I. Cutler, Chad A. Mirkin, Small 2009, 5, No. 6, 646
  4. "Oligonucleotide loading determines cellular uptake of DNA-modified gold nanoparticles," David A. Giljohann, Dwight S. Seferos, Pinal C. Patel, Jill E. Millstone, Nathaniel L. Rosi, and Chad A. Mirkin, Nano Lett. 7, 3818 (2007)
  5. "Efficient Small Molecule Bulk Heterojunction Solar Cells with High Fill Factors via Pyrene-Directed Molecular Self-Assembly," Olivia P. Lee, Alan T. Yiu, Pierre M. Beaujuge, Claire H. Woo, Thomas W. Holcombe, Jill E. Millstone, Jessica D. Douglas, Mark S. Chen, Jean M. J. Fréchet, Adv. Mater. 23, 5359 (2011)
Recent Publications: 
  1. "Correlating Carrier Density and Emergent Plasmonic Features in Cu2-xSe Nanoparticles," Marbella LE, Gan XY, Kaseman DC, Millstone JE., Nano Lett. 2017
  2. "Ligand density quantification on colloidal inorganic nanoparticles," Ashley M. Smith, Kathryn A. Johnston, Scott E. Crawford, Lauren E. Marbella and Jill E. MillstoneAnalyst 142, 11-29 (2017)
  3. "Imaging Energy Transfer in Pt-Decorated Au Nanoprisms via Electron Energy-Loss Spectroscopy," Sarah Griffin, Nicholas P. Montoni, Guoliang Li, Patrick J. Straney, Jill E. Millstone, David J. Masiello, and Jon P. Camden, J. Phys. Chem. Lett. 7, 3825 (2016)
  4. "Conceptual Analysis for Nanoscience," Julia R. Bursten, Michael J. Hartmann, and Jill E. MillstoneJ. Phys. Chem. Lett. 7, 1917 (2016)
  5. "Structural and Optical Properties of Discrete Dendritic Pt Nanoparticles on Colloidal Au Nanoprisms," Rowan K Leary, Anjli Kumar, Patrick J Straney, Sean M Collins, Sadegh Yazdi, Rafal E Dunin-Borkowski, Paul A Midgley, Jill E Millstone, Emilie Ringe, J. Phys. Chem. C 120, 20843 (2016)

Quantum-Engineered Nanoscale Alloys So Bright They Could Have Potential Medical Applications

  • By Aude Marjolin
  • 14 May 2013

Alloys like bronze and steel have been transformational for centuries, yielding top-of-the-line machines necessary for industry. As scientists move toward nanotechnology, however, the focus has shifted toward creating alloys at the nanometer scale—producing materials with properties unlike their predecessors.

Now, researchers led by PQI faculty Jill Millstone demonstrate that nanometer-scale alloys possess the ability to emit light so bright they could have potential applications in medicine. The findings have been published in the Journal of the American Chemical Society.