NSF Workshop on Emerging Opportunities of Nanoscience to Energy Conversion and Storage

 

Appendix C: Abstracts of Workshop Speakers


name = Thom LaBean
affiliation = Duke University
address = 329 Gross Chemistry Bldg, Duke University, Durham, NC
phone = (919) 660-1565
fax = (919) 660-1605
email = thomas.labean@duke.edu
hompage = www.cs.duke.edu/~thl
title = Self-Assembling DNA Nanostructures and DNA-Based Nanofabrication
abstract = DNA is well-known as the predominant chemical for duplication and storage of genetic information and has recently become important as an engineering material for construction of micron-scale objects with nanometer-scale feature resolution.  Properly designed synthetic DNA can be used as programmable building blocks that will, via specific hybridization of complementary sequences, reliably self-organize to form desired structures and superstructures.  Such engineered nanostructures are suitable for use as templates and scaffolds for imposing specific patterns on various other materials.  Given diverse mechanical, chemical, catalytic, and electronic properties of these specifically patterned heteromaterials, DNA self-assembly techniques hold great promise for bottom-up nanofabrication in wide ranging fields of technology. This talk will present recent results and potential approaches for using DNA nanostructures in energy related applications.
presentation = www.cs.duke.edu/~thl/NSFEnergy.pdf
homepage = www.cs.duke.edu/~thl
technologyresults = Fixed-size, fully-addressable DNA nanoassemblies.
Large area (mm2) DNA lattices.
Active DNA/metal nanoparticle systems.
 
relevantpapers = S.-H. Park, C. Pistol, S.- J. Ahn, J. H. Reif, A. Lebeck, C. Dwyer, and T.H. LaBean (2005)  Finite-size, Fully-Addressable DNA Tile Lattices Formed by Hierarchical Assembly Procedures. (accepted for publication, Angew. Chem. Int. Ed).
 
Kurt V. Gothelf and Thomas H. LaBean (2005) DNA-programmed assembly of nanostructures. Organic & Biomolec. Chem. 3, 4023.
 
S-H. Park, P. Yin, Y. Liu, J.H. Reif, T.H. LaBean, and Hao Yan (2005) Programmable DNA Self-assemblies for Nanoscale Organization of Ligands and Proteins. Nano Letters 5, 729-733.
 
S-H. Park, R. Barish, H. Li, J.H. Reif , G. Finkelstein , H. Yan, and T.H. LaBean (2005) Three-Helix Bundle DNA Tiles Self-assemble into 2D Lattice or 1D Templates for Silver Nanowires. Nano Letters 5, 693-696.
 
Sung Ha Park, Hao Yan, John H. Reif, Thomas H. LaBean and Gleb Finkelstein (2004) Electronic nanostructures templated on self-assembled DNA scaffolds.  Nanotechnology 15, S525-S527.
 
D. Liu, S- H. Park, J. H. Reif, and T.H. LaBean (2004) DNA nanotubes self-assembled from TX tiles as templates for conductive nanowires. Proc. Nat. Acad. Sci., USA 101, 717-722.
 
H. Li, S- H. Park, J. H. Reif, T. H. LaBean, and Hao Yan, (2004) DNA Templated Self-Assembly of Protein and Nanoparticle Linear Arrays, J. Am. Chem. Soc. 126, 418-419.
 
H. Yan, S.H. Park, G. Finkelstein, J.H. Reif, and T.H. LaBean (2003) DNA-Templated Self-Assembly of Protein Arrays and Highly Conductive Nanowires. Science 301, 1882-1884.
 
comments = 
photovoltaics = yes
submit = Submit
 
 
 
====================

name = Theodorian Borca-Tasciuc

affiliation = Rensselaer Polytechnic Institute

address = 110 8th Street JEC 2030 Troy, NY 12180

phone = 518 276 2627

fax = 518 276 6025

email = borcat@rpi.edu

hompage = nanotec.meche.rpi.edu

title = Thermoelectric Transport in Bismuth Telluride Nanoassemblies

abstract = Highly efficient solid-state thermoelectric energy conversion requires materials with a large thermoelectric figure of merit. Engineering the electric and thermal transport in nanostructures by employing quantum and size effects has emerged as a candidate for factorial enhancements in the thermoelectric figure of merit. This work presents our exploratory investigations of thermoelectric transport in Bi2Te3 nanostructured assemblies. Nanoparticles of 3-15nm diameter and rod-shaped nanocrystals of 20- to 85-nm-diameter and ~1micrometer long are grown using wet chemistry methods. The nanostructures are functionalized with desired termini for dispersion in solutions and controlled assembly. Films were obtained by drop-casting and drying the dispersed nanostructures solutions on glass substrates instrumented with microelectrodes for electrical conductivity and Seebeck characterization in the 80-300K temperature range. The thermal conductivity measurement is performed u!

sing a scanning hot probe technique, where the thermal resistance of a heated AFM thermal probe is measured when the probe is in contact with the film. The presentation will discuss the effect of the film structure, growth conditions, and temperature annealing on the thermoelectric transport.

presentation =

homepage = nanotec.meche.rpi.edu

technologyresults = 1. thermal conductivity reduction in nanostructures

2. theoretical models for thermoelectric transport in quantum dot arrays

3. self-assembly

4. growth of high quality crystalline nanostructures by wet-chemistry methods

 

relevantpapers = Venkatasubramanian, R., Siivola, E., Colpitts, T., and OÕQuinn, B., 2001 ÒThin-film thermoelectric devices with high-room temperature figures of merit,Ó Nature 413, 597.

Harman, T. C.; Taylor, P. J., Walsh, M. P., and LaForge, B. E., 2002, ÒQuantum dot superlattice thermoelectric materials and devices,Ó Science 297, 2229.

Chen, G., Dresselhaus, M. S., Dresselhauss, G., Fleurial, J. P., and Caillat, T., 2003, ÒRecent developments in thermoelectric materials,Ó International Materials Reviews 48, 45.

Balandin Alexander A. and Lazarenkova Olga L., ÒMechanism for thermoelectric figure-of-merit enhancement in regimented quantum dot superlattices,Ó Appl. Phys. Lett. 82, 415 (2003)

 

comments =

thermoelectrics = yes

submit = Submit


name = John N. Harb

affiliation = Brigham Young University

address = 270 Clyde Building

phone = 801-422-4393

fax = 801-422-0218

email = john_harb@byu.edu

hompage =

title = The Application of Nanotechnology to Electrochemical Energy Storage

abstract = This presentation will begin with a brief description of the challenges and limiting factors associated with electrochemical energy storage, with a particular focus on batteries. A few applications that range in size from very large to nano will be considered and specific needs identified. The use of nanoscience and technology to address these needs will then be illustrated. Strategies include: 1) the development of new materials whose properties are derived from unique nanoscale physics, 2) the use of nanofeatures and structures to improve the performance of existing materials, 3) enhancement of our fundamental understanding of nanoscale processes to enable optimization of existing energy storage devices and the development of new devices, 4) the development of new nano-derived methods for manufacturing and assembly of energy storage materials and devices, and 5) the development of multifunctional engineering materials designed for specific applications that i!

nvolve electrochemical energy storage. These strategies will be illustrated with examples from a variety of investigators. Future opportunities and potential obstacles will also be discussed.

presentation =

homepage =

technologyresults =

relevantpapers =

comments =

submit = Submit


name = Katsuyo Thornton

affiliation = University of Michigan

address = 2300 Hayward Street, Ann Arbor, MI 48109

phone = 734-615-1498

fax = 734-763-4788

email = kthorn@umich.edu

hompage = http://msewww.engin.umich.edu/people/faculty/thornton

title = Experiments and Simulations of Three-Dimensional Nanostructures of Solid-Oxide Fuel Cell Electrode

abstract = Fuel cells are the focus of active research because they can provide a more efficient and pollution-free method for converting chemical energy to electricity. Fuel cell electrodes typically have a complex nanostructure that determines their electrochemical efficiency and their lifetime. However, current methods for controlling electrode structure to achieve higher efficiency are very limited. Our ongoing collaborative research on solid-oxide fuel cell electrodes is described. The team brings together both experimental and modeling expertise to reconstruct and characterize the three-dimensional nanostructure, measure electrochemical performance, and model and simulate the nanostructural evolution and its consequence on fuel cell performance. The analyses of the results are expected to lead to new methods for improving the efficiencies of solid-oxide fuel cells.

presentation = TBD

homepage = TBD

technologyresults =

relevantpapers =

comments = - Collaborative efforts consisting of experimental and modeling/simulation/theoretical work

- Characterization of three-dimensional microstructures using computationally intensive methodologies

- Development of 3D microstructure-performance relationship

fuelcellandbatteries = yes

submit = Submit


name = Kevin Stokes

affiliation = University of New Orleans

address = Dept. of Physics

phone = 985-781-6085

fax =

email = klstokes@uno.edu

hompage =

title = One-dimensional Nanoparticle Composites for Thermoelectric Applications

abstract = Engineered, nanometer-scale semiconductor materials are now being developed to increase thermoelectric efficiency. While current successes in low-dimensional thermoelectrics are attributed mainly to selective phonon scattering, much larger enhancements are predicted in systems in which the confinement of the carriers produces peaks in the density of states near the Fermi energy. To this end, we are producing quasi-one-dimensional structures containing semiconducting nanoparticles connected by conducting polymers. The Seebeck coefficient of the semiconductor component should be enhanced due to carrier confinement while the conducting polymer provides high electrical to thermal conductivity ratio interconnects between the particles. We present the chemical synthesis, assembly and properties these composites consisting of strands of lead telluride (PbTe) nanoparticles connected by polythiophene. The nanoparticles are made by high-temperature organometallic chemical !

synthesis. The nanoparticles are treated with various organic molecules to provide compatibility with the polymer and improve electrical connectivity. The nanoparticle/polymer solution is dispersed in a Langmuir-Blodgett trough and rolled into strands through overcompression. The resulting nanoparticle-polymer strands contain a low-volume fraction of polymer (typically ~5%) and can be lifted of the water surface. We will discuss the details of the synthesis as well as the issues concerning electronic conduction in these materials and scale-up of the processes.

presentation =

homepage =

technologyresults = The work of Alivisotos at UC Berkley is of particular note. This group is developing large-scale chemical synthesis techniques for high-quality, nanoparticle production. While applied to photovoltaics, large-scale synthesis of nanometerials is key to the realization of many energy-conversion technologies.

relevantpapers = 1. Harman, T.C., Taylor, P.J., Walsh, M.P., and LaForge, B.E., Quantum dot superlattice thermoelectric materials and devices. Science 297, p. 2229 (2002).

2.

Venkatasubramanian, R., Siivola, E., Colpitts, T., and O'Quinn, B., Thin-film thermoelectric devices with high room-temperature figures of merit. Nature 413, p. 597 (2001).

comments =

thermoelectrics = yes

submit = Submit


name = Alexis Abramson

affiliation = Case Western Reserve University

address = 10900 Euclid Ave

phone = 216-368-4191

fax = 216-368-3007

email = alexis.abramson@case.edu

hompage =

title = Novel Thermoelectric Materials for Improved Performance: Nanocomposites and Bio-Inspired Hydrogels

abstract = Thermoelectric devices are attractive candidates for heat removal or energy production applications because they do not contain moving parts, are environmentally benign, and may be easily incorporated into small-scale technologies. The use of thermoelectric devices is not widespread today, but even marginal improvements in performance can have enormous impact on their future application. The work presented will specifically discuss two novel approaches to the development of thermoelectric materials. Nanocomposite systems comprised of conducting polymers and Bi nanoparticles are discussed. The high quality nearly mono-dispersed nanoparticles are synthesized via pyrolysis of reagents into a hot coordinating solvent. The nanocomposites are fabricated by combining the nanoparticles with a monomer solution of aniline, followed by polymerization upon spin coating of the solution on a substrate to form nanocomposite films. Thermal conductivity, electrical conductivity an!

d Seebeck coefficient measurements of initial composites will be reported. The second approach to the development of novel materials comes from looking to nature for guidance. Some species of shark use thermoelectrics to sense temperature differentials in their surroundings by using electrosensing organs consisting of a nerve set at the end of a pore which is filled with an extracellular gel comprised of sea water and a small percentage of glycoprotein. Our experimental work has shown that the shark gel exhibits an unusually high Seebeck coefficient, and we have provided a qualitative explanation as to why an enhanced Seebeck coefficient results. These experiments have helped guide ongoing research towards synthesizing artificial gels with exceptionally high Seebeck coefficients by carefully choosing appropriate electrolyte solutions combined with a high concentration of macromolecules comprised of densely packed charged groups. As a result, a new class of bio-inspired ther!

moelectric systems exhibiting superior Seebeck coefficients wi!

ll be de

monstrated.

presentation =

homepage =

technologyresults = Nanoscale characterization of thermal and electrical properties

relevantpapers =

comments = The development of novel high performance thermoelectric materials will require very productive collaboration between the chemists who make the materials, and the engineers/scientists who design and characterize the materials.

thermoelectrics = yes

submit = Submit


name = Kevin Pipe

affiliation = University of Michigan

address = 2146 G. G. Brown / 2350 Hayward St. / Ann Arbor, MI 48109-2125

phone = 734-763-6624

fax = 734-647-3170

email = pipe@umich.edu

hompage = http://me.engin.umich.edu/peopleandgroups/faculty/pipe_kevin.shtml

title = Thermoelectric Energy Conversion in Active Devices

abstract = Heating is a significant problem for electronic devices, leading to thermal rollover in the performance characteristics of nearly all such devices. As electronic device sizes shrink through large-scale integration, extreme heat fluxes well above 100 W/cm2 can be generated over microscale and nanoscale areas. This talk will cover the use of thermoelectric structures for energy harvesting in active electronic devices, at size scales ranging from the macroscale (in which nanostructured bulk thermoelectric materials can harvest energy over large areas) to the microscale (in which integrated thermoelectric structures can recover waste heat energy from individual electronic devices). Also discussed will be ways in which electronic devices themselves can make use of internal thermoelectric effects to achieve higher efficiency.

presentation = http://www-personal.engin.umich.edu/~pipe/nanoenergy/

homepage = http://www-personal.engin.umich.edu/~pipe/

technologyresults = High-ZT thermoelectrics achieved through nanostructured materials

Hybrid organic/inorganic nanostructured large-area photovoltaic devices with high efficiency

 

relevantpapers = Harman, T. C., et al. (2002). "Quantum dot superlattice thermoelectric materials and devices." Science 297: 2229.

 

Venkatasubramanian, R., et al. (2001). "Thin-film thermoelectric devices with high room-temperature figures of merit." Nature 413: 597.

 

Bilc, D., et al., "Resonant States in the electronic structure of the high performance thermoelectrics AgPbmSbTe2+m: the role of Ag-Sb microstructures", Physical Review Letters, v 93, n 14, 1 Oct. 2004, p 146403/1-4.

 

comments = Important opportunities exist in the fabrication of hybrid organic/inorganic nanostructured thermoelectric devices, which can achieve high ZT over large areas with low cost. Such devices thus far have been difficult to achieve (A. R. Abramson et al., J. MEMS 13, 505 (2004) and capture a wide range of issues that are important for nano-energy research: the use of inorganic nanostructures to effectively increase carrier mobility in organic materials, energy transport across organic/inorganic interfaces, reliable electrical connections to nanostructures and the placement/alignment of these nanostructures, modeling the Seebeck coefficient in nanostructure superlattices, etc.

thermoelectrics = yes

submit = Submit


name = James C. Ellenbogen

affiliation = Nanosystems Group, The MITRE Corporation

address = 7515 Colshire Dr., Mailstop H619, McLean, VA 22102

phone = 703-983-5930

fax = 703-983-5963

email = ELLENBGN@mitre.org

hompage = www.mitre.org/tech/nanotech

title =

abstract =

presentation =

homepage =

technologyresults =

relevantpapers =

comments =

fuelcellandbatteries = yes

submit = Submit


name = Josef Michl
affiliation = University of Colorado, Department of Chemistry & Biochemistry
address = 215 UCB, Boulder, Colorado 80309-0215
phone = 303-492-6519
fax = 303-492-0799
email = michl@eefus.colorado.edu
hompage = http://www.colorado.edu/chem/DEC/people/michlj.html
title = Improving the Efficiency of Excitonic Solar Cells
abstract =               The Graetzel cell, based on TiO<sub>2</sub> nanoparticles coated with a sensitive dye, is cheap to produced but its efficiency is only about 10%.  Some opportunities for increasing both the current and the voltage produce will be discussed and our present activities as well as future plans for implementing them will be outlined.
presentation = 
homepage = 
technologyresults = controlled self-assembly, materials with controlled redox properties
relevantpapers = Magnera, T. F.; Michl, J. ÒTwo-Dimensional Supramolecular Chemistry with Molecular TinkertoysÓ, Proc. Nat. Acad. Sci. USA 2002, 99, 4788.
Varaksa, N.; Posp’šil, L.; Magnera, T. F.; Michl, J. ÒSelf-Assembly of a Metal Ion Bound Monolayer of Trigonal Connectors on Mercury.  An Electrochemical Langmuir TroughÓ, Proc. Nat. Acad. Sci. USA 2002, 99, 5012.
comments = controlled self-assembly, materials with controlled redox properties
photovoltaics = yes
submit = Submit

name = Shanhui Fan
affiliation = Stanford University
address = 801 Tolman Drive
phone = 1-650-724-4759
fax = 1-650-725-3890
email = shanhui@stanford.edu
hompage = http://www.stanford.edu/group/fan
title = Nanophotonics and energy conversion
abstract = In this talk, we will discuss some of our recent works related to solar and thermal photovotaics.
presentation = 
homepage = http://www.stanford.edu/group/fan
technologyresults = The intense efforts related to transmission through subwavelength metallic apertures, and the demonstration of blackbody radiation control in phtonic crystals. 
relevantpapers = Lin et al, APL, 83, 380 (2003)
Shin et al, PRB, 72, 085436 (2005)
comments = In the area of nanophotonics, interesting opportunities for energy related applications include enhanced photon transport through metallic structures; control of blackbody radiation; and field concentration and enhancement of light-matter interactions.
photovoltaics = yes
submit = Submit

name = Thomas Renz
affiliation = Air Force Research Laboratory
address = AFRL/IFTC, 26 Electronic Parkway, Rome, NY, 13441
phone = 315-330-3423
fax = 
email = renzt@rl.af.mil
hompage = 
title = 
abstract = 
presentation = 
homepage = 
technologyresults = 
relevantpapers = 
comments = 
photovoltaics = yes
submit = Submit

name = Peng Yin 
affiliation = Caltech
address = MS 136-93, Caltech, Pasadena, CA 91125
phone = 626-395-8839
fax = 626-395-1701
email = py@caltech.edu
hompage = http://pengyin.org
title = N.A.
abstract = N.A.
presentation = N.A.
homepage = 
technologyresults = 
relevantpapers = 
comments = 
submit = Submit

name = Morley O. Stone
affiliation = DARPA / DSO
address = 3701 N Fairfax Dr, Arlington, VA 22203
phone = 571-218-4504
fax = 703-807-1714
email = morley.stone@darpa.mil
hompage = 
title = 
abstract = 
presentation = 
homepage = 
technologyresults = 
relevantpapers = 
comments = 
submit = Submit

name = Stuart Lindsay
affiliation = Arizona State University
address = Biodesign Institute, Tempe, AZ 85287-5601
phone = 480 965 4691
fax = 480 727 2378
email = Stuart.Lindsay@asu.edu
hompage = http://green.la.asu.edu
title = Molecules and nano architecture for charge transport
abstract = This talk will examine progress and possibilities for building 'moleular wires' for charge transport in molecular photovoltaics.
presentation = 
homepage = http://green.la.asu.edu
technologyresults = DNA nanotechnology for self-assembly of photonic structures
Recent developments in "molecular wires" 
relevantpapers =  ÒReproducible Measurement of Single-Molecule ConductivityÓ X. D. Cui, A. Primak, X. Zarate, J. Tomfohr, O. F. Sankey, A. L. Moore, T. A. Moore, D. Gust, G. Harris and S. M. Lindsay, Science 294, 571-574 (2001).
ÒElectronic Decay Constant of Carotenoid Polyenes from Single-Molecule MeasurementsÓ  He, J.; Chen, F.; Li, J.; Sankey, O. F.; Terazono, Y.; Herrero, C.; Gust, D.; Moore, T. A.; Moore, A. L.; Lindsay, S. M.; 
J. Am. Chem. Soc.; (Communication); 2005; 127(5); 1384-1385.
 ÒA Molecular Switch Based on Potential-Induced Changes of Oxidation StateÓ  Fan Chen, Jin He, Colin Nuckolls, Tucker Roberts, Jennifer E. Klare, and Stuart Lindsay, Nano Letters, 5 503-506 (2005).
comments = rational design and assembly of photovoltaics
photovoltaics = yes
submit = Submit

name = Hao Yan
affiliation = Arizona State University
address = 
phone = 1-480-727-8570
fax = 1-480-727-2378
email = hao.yan@asu.edu
hompage = 
title = DNA based self-assembly of hierarchical nanostructures
abstract = DNA is an extraordinarily versatile material for designing nano-architectural motifs, due in large part to its programmable G-C
and A-T base pairing into well-defined secondary structures.  DNA
nanotechnology is further empowered by well-established methods for
purification and structural characterization and by solid-phase
synthesis, so that any designer DNA strand can be constructed. In this
talk, I will  present our recent experimental progress to utilize novel
DNA nanostructures for self-assembly as well as for templates in the
construction of patterned protein and nanoparticle arrays.
 
presentation = 
homepage = 
technologyresults = 
relevantpapers = 
comments = 
photovoltaics = yes
submit = Submit

name = David Carlson
affiliation = BP Solar
address = 630 Solarex Court, Frederick, MD 21703
phone = (301) 698-4256
fax = (301) 698-4305
email = Dave.Carlson@bp.com
hompage = http://www.bpsolar.com
title = PV Technologies for the Future
abstract = BP Solar is supporting research for future PV technologies at a number of universities and institutes.  This talk will provide an overview on these programs and discuss the challenges to developing efficient photovoltaic devices using nanotechnology.
presentation = 
homepage = 
technologyresults = 1. Need to develop device structures that can efficiently absorb solar radiation and that allow efficient collection of the photogenerated carriers.
2. Need to develop methods of creating nanocomposite solar cells with large built-in potentials.
3. Need to develop nanocomposite materials that can be used in efficient solar cells and that can be produced at low cost and that are non-toxic.
4. Need to develop contacts to nanocomposite materials that will have either form heterojunctions or low resistance contacts.
5. Need to develop efficient nanocomposite solar cells that are stable and capable of > 20 years of operational life.
 
relevantpapers = 
comments = 
photovoltaics = yes
submit = Submit

name = Nadrian C. Seeman
affiliation = New York University
address = Dept. of Chemistry, New York, NY 10003
phone = 212-998-8395
fax = 212-260-7905
email = ned.seeman@nyu.edu
hompage = seemanlab4.chem.nyu.edu
title = DNA:  Not Merely the Secret of Life
abstract =               Structural DNA nanotechnology uses the concept of reciprocal exchange between DNA double helices to produce branched DNA motifs, like Holliday junctions, or related structures, such as double crossover (DX), triple crossover (TX), paranemic crossover (PX) and DNA parallelogram motifs.  We have worked since the early 1980's to combine DNA motifs, using sticky-ended cohesion, to produce specific structures. From branched junctions, we have constructed DNA stick-polyhedra, whose edges are double helices, and whose vertices are the branch points of DNA branched junctions. These include a cube, a truncated octahedron, and an irregular graph.  Recently, we have begun to template the topology of industrial polymers, such as nylon, with DNA-like scaffolds and to organize metallic nanoparticles.
               Nanorobotics are key to the success of all activities in nanotechnology. PX DNA has been used to produce a robust sequence-dependent device that changes states by varied hybridization topology.  The sequence-dependent nature of this device means that a variety of them attached to a motif can all be addressed individually.  Recently, we have used this device to make a translational machine.  We have also built a sequence-driven nanobot.
               A central goal of DNA nanotechnology is the self-assembly of periodic matter. We have constructed micron-sized 2-dimensional DNA arrays from DX, TX and two kinds of parallelogram motifs. We can produce specific designed patterns visible in the AFM from DX and TX molecules. We can change the patterns by changing the components, and by modification after assembly.
 
presentation = seemanlab4.chem.nyu.edu
homepage = seemanlab4.chem.nyu.edu
technologyresults = Nanodevices, polymer and nanoparticle organization.
relevantpapers = 1.S. Liao and N.C. Seeman, Translation of DNA Signals into Polymer Assembly Instructions, Science, in press (2004).
2.L. Zhu, P.S. Lukeman, J. Canary & N.C. Seeman, Nylon/DNA:  Single-Stranded DNA with Covalently Stitched Nylon Lining, J. Am. Chem. Soc. 125, 10178-10179 (2003).
3.H. Yan, X. Zhang, Z. Shen and N.C. Seeman, A Robust DNA Mechanical Device Controlled by Hybridization Topology, Nature 415, 62-65 (2002).
4.W.B. Sherman and N.C. Seeman, A Precisely Controlled DNA Bipedal Walking Device, NanoLett. 4, 1203-1207 (2004).  
5.W. Shen, M. Bruist, S. Goodman & N.C. Seeman, A Nanomechanical Device for Measuring the Excess Binding Energy of Proteins that Distort DNA, Angew. Chem. Int. Ed. 43, 4750-4752 (2004).
 
comments = The capabilities that we are able to provide is the ability to organize chemical species on the nanometer scale.  These include polymers, nanoparticles, and biological components.  We expect that this capability will enable efficient assembly of electronic devices, and other species with the precision on the nanoscale now found only in the living cell.
photovoltaics = yes
submit = Submit

name = George Schatz
affiliation = Northwestern University
address = Northwestern University
phone = 847-491-5657
fax = 847-491-7713
email = schatz@chem.northwestern.edu
hompage = http://www.chem.northwestern.edu/~schatz
title = Modeling the optical and structural properties of nanoparticle arrays and DNA-linked nanoparticle aggregates
abstract = Arrays and aggregates of silver and gold nanoparticles have a variety of interesting optical and structural properties that have only begun to be explored.  In this talk I will describe theory and modeling studies of these properties, emphasizing two points:  how the electromagnetic coupling of nanoparticles in arrays and aggregates influence optical spectra, and how DNA hybridization that produces nanoparticle aggregates leads to materials with unusual structural and thermal melting properties.  
 
A key point of our work on the optical properties of nanoparticle arrays is that the dipolar coupling between nanoparticles can in some cases be extremely long range, leading to narrow lineshapes in plasmon resonances, and the ability to propagate excitation for 100 µm or more.
 
Our work on DNA-linked aggregates has emphasized the narrow melting transitions that have proven important to the use of these materials in DNA sensing.  I will discuss recent work in understanding the mechanism of the narrow melting, as well as our work in understanding the effect of irreversibility in the hybridization kinetics on the aggregate structures.
 
presentation = 
homepage = http://www.chem.northwestern.edu/~schatz
technologyresults = 1. Plasmon enhanced absorption and photochemistry.  This has the capability of enhancing interfacial absorption and photochemical processes by orders of magnitude.  There have been a number of advances in our understanding of the conditions need to achieve useful results.
 
2. Building useful structures involving metal, dielectric and semiconductor nanoparticles using DNA linkers.  The technology for using DNA linkers to create aggregates of metal, semiconductor and dielectric nanoparticles is rapidly developing, with a number of recent reports in which different materials have been adapted to this approach.  The usefulness of this for photoabsorption and photochemistry remains to be demonstrated.
relevantpapers = Controlling plasmon line-shapes through diffractive coupling in linear arrays of cylindrical nanoparticles fabricated by electron beam lithography,  E. M. Hicks, S. Zou, G. C. Schatz, K. G. Spears, R. P. Van Duyne, L. Gunnarsson, T. Rindzevicius, B. Kasemo, M. Kall, Nano Letters, 5, 1065-70 (2005).
 
Plasmonic Materials for Surface-Enhanced Sensing and Spectroscopy, A. J. Haes, C. L. Haynes, A. D. McFarland, S. Zou, G. C. Schatz, and R. P. Van Duyne, MRS Bulletin, 30, 368-375 (2005).
 
What Controls the Melting Properties of DNA-Linked Gold Nanoparticle Assemblies?, Rongchao Jin, Guosheng Wu, Zhi Li, Chad A. Mirkin, and George C. Schatz, J. Am. Chem. Soc., 125, 1643 1654 (2003).
 
 
comments = Here are three ideas for research topics:
 
1. Photophysical interactions of semiconductor and metal nanoparticles.  We really need to understand the tradeoff between enhanced absorption and quenching when semiconductor and metal nanoparticles are placed in close proximity.
 
2. Using DNA structures to position semiconductor and metal nanoparticles for optimum photovoltaic performance. 
 
3. Photophysical properties of dye molecules interacting with metal/semiconductor nanoparticle structures.
photovoltaics = yes
submit = Submit

name = Liwei Lin
affiliation = University of California at Berkeley
address = 5126 Etcheverry, Berkeley, CA 94720-1740
phone = (510)643-5495
fax = (510)643-5599
email = lwlin@me.berkeley.edu
hompage = http://www.me.berkeley.edu/~lwlin/
title = Bioelectric PEM Fuel Cells
abstract = Continuous and long-term power supply generated directly from biological organisms could have great impact for nano, micro to macro systems.  In futuristic applications, for example, diagnosing medical problems and delivering drugs from inside the body has been a dream of doctors since Isaac Asimov's 1966 science fiction classic ``Fantastic Voyage,'' in which a group of doctors were miniaturized and injected into a patient to remove a blood clot.  Doctors can't be shrunk, but any future engineering device that resembles the Òfantastic voyageÓ will requires power supply.  In large-scale system applications, implantable medical devices such as spinal cord stimulator and drug delivery devices used in spinal drug infusion therapy for pain relief applications also require power.  Micro power generation is an important element for small-scale systems and two types of power systems will be discussed in this talk: disposable micro batteries and microbial fuel cells.  The motivation of the microbial fuel cells came from the observation of the energy cycle from ÒnatureÓ - energy in the form of light coming from sun assists the photosynthesis process in green plants that convert carbon dioxide and water into glucose.  Animals take green plant as the food for glucose support and in the aerobic respiration process, convert glucose and oxygen into carbon dioxide, water and ATP (adenosine triphospate).  We propose to extract energy from these energy translation processes by building up artificial fuel cells to interact with living bacteria for engineering applications, such as to power nano or micro devices. 
presentation = 
homepage = http://www.me.berkeley.edu/~lwlin/
technologyresults = 
relevantpapers = 
comments = microbial/photosynthetic energy generation
fuelcellandbatteries = yes
submit = Submit

name = Paul Braun
affiliation = University of Illinois at Urbana-Champaign
address = 1304 West Green St, Urbana, IL 61801
phone = 217-244-7293
fax = 217-333-2736
email = pbraun@uiuc.edu
hompage = braungroup.beckman.uiuc.edu
title = Adding Functionality to Self-assembled 3D Nanophotonic Materials
abstract = Three-dimensional photonic crystals offer interesting opportunities for scientific exploration and formation of functional materials and structures. Simple periodic photonic crystals, such as formed through colloidal crystallization have some interesting optical properties, however, many devices, such as lasers, waveguides, and chemical sensors will require the incorporation of new materials and aperiodic defect structures within the photonic crystal.  After a brief discussion on the optical properties of photonic crystals and photonic band gap materials, I will present our results on the use of multiphoton polymerization, electrochemistry, and chemical vapor deposition to enhance the functionality of colloidal photonic crystals. Through multiphoton polymerization we can incorporate aperiodic defects with dimensions on the order of the wavelength of light within photonic crystals. The defect structures formed include 3-D waveguides with sharp bends and embedded optical cavities. Critical to formation of an optical device is a direct pathway to enhance the refractive index contrast of the structure without disrupting the 3D periodicity. Most polymers simply do not have a sufficiently high refractive index to form a photonic band gap structure, and thus strategies to enhance the refractive index contrast will be presented.
presentation = 
homepage = braungroup.beckman.uiuc.edu
technologyresults = In photonic nanosystems, the materials science for creating complex structures at the nanoscale has finally reached the point where one can just about create any structure of anything.  The theoretical tools for simulating the properties of complex structures at the nanoscale is now also fairly well developed.  Now it is often the question as to what structures one should form.  This requires very close coupling between theory and experiment, which we are beginning to see, but needs to be emphasized to a greater extent.
relevantpapers = 
comments = Although one can create a truly well defined complex nanoscale structure of about any material, at least over a limited lengthscale, it remains a major challenge to form these structures over large areas, or even into bulk materials.  This to me represents a major, and generally unaddressed challenge and opportunity for future research into nano-energy.  Energy by its very nature often requires materials at the macroscale, so as long as we can only create nanostructures at the nanoscale, there will be limited impact for real world energy systems.
photovoltaics = yes
submit = Submit
 

name = Tianwei Lin
affiliation = The Scripps Research Institute
address = 10550 N. Torrey Pines Road, La Jolla, CA 92037
phone = 858-784-7730
fax = 858-784-7775
email = twlin@scripps.edu
hompage = 
title = Assembly of Nano-Materials on the Scaffold of an Icosahedral Virus
abstract = Introduction
A quintessential tenet of nano-technology is the self-assembly of components in nanometer scale to devices.  While small molecules with special properties can be synthesized, functional connectivity among different components in a predetermined pattern is generally difficult to achieve.  Biological macromolecule systems, with their versatility, programmability through genetic engineering and propensity to form arrays, are generally more amenable for self-assembly, either for direct use as devices or as templates for patterning small molecules.  Additionally, biocompatibility, which is essential for biological applications, is an inherent property of the macromolecules.  The ideal properties of a biological system for nano-applications include high yield, structural definition to atomic resolution and high degree of stability to heat and organic solvents.  We exploit icosahedral viruses, especially a Cowpea mosaic virus (CPMV), for applications in nano-medicine and -technology.  In addition to the above properties, the icosahedral virus particles are associated with high symmetry, polyvalency, the capacity to carry large cargos and extensive surfaces for functional engineering.  
 
Self-assembly through position-specific chemistry
CPMV as the scaffold for thiol chemistry
There are no free sulfhydryl groups on the exterior CPMV surface as shown in the crystal structure. Thiol-addressable CPMV mutants with cysteines on the exterior surface were generated by insertion of Cys-containing peptides or oligonucleotide-directed mutagenesis.  A mutant, vEFa, with the Cys residues placed between positions 298 and 299 of the bE-bF loop in the large subunit was the most extensively characterized and the labeling of the 60 reactive thiol groups per particle can be driven to near completion. The mutant virus was reacted with monomaleimido-Nanogold¨ (Nanoprobes, Inc.) and the derivatized particles were imaged by cryo electron microscopy and image reconstruction. The gold particles were clearly visible at the positions of the inserted cysteine residues in the electron density map, demonstrating that a virus could function as a convenient and programmable platform for chemical reactions.  
 
Amine reactivity for the assembly of supramolecues
For directional and controlled heterologous attachment, at least two types of reactive groups would be required.  In addition to thiol groups, amine groups are also highly reactive in proteins. Amine groups can be contributed by either the N-terminus of a polypeptide or by the side chains of Lys residues.  Since the N-termini of both CPMV coat proteins are in the capsid interior, the only reactive amine groups on the virus exterior surface will be the exposed Lys side chains.  There are 5 Lys residues per asymmetric unit on the capsid exterior. Successive mutations resulted in virus particles with different combinations of Lys residues.  Two mutants, vK138 and vK299, were generated by retaining the single reactive lysine residues, Lys138 and Lys299, and mutating the other 4 Lys residues to Arg.  These two mutants were treated with monosulfo NHS NANOGOLD¨ (Nanoprobes, Inc.) to generate metal-decorated virus particles. Structural analysis of the conjugates by cryo electron microscopy and image reconstruction showed specific labeling of the targeted lysine residues.  There were striking differences in the presentation of the gold on different mutants, suggesting that the local environment of the targeted lysine residue influenced the presentation of the attached ligand.
 
Potential applications
Fabrication of photonic band gap materials 
CPMV can be crystallized in at least 3 space groups.  These are 3D arrays with ordering to near atomic precision.  CPMV crystals were used as prefabricated molds for infiltration of metals to generate metallic blocks with uniformed cavities, which could find applications as photonic band gap materials and catalysts.
 
Molecular electronics 
Nano-wires were assembled on the surface of CPMV with thiol groups in designed patterns. The conductance was measured by scanning tunneling microscopy
 
H2 evolution
We have shown that the virus can be attached with porphyrin, a light-harvesting compound, and be metallized with Pd, a catalyst for hydrogen evolution. A future possibility is to produce a light-driven device for H2 evolution by assembly of porphyrin molecules and Pd at the designated positions on a single virus particle.
 
presentation = 
homepage = 
technologyresults = 
relevantpapers = 
comments = Assembly of nano-devices for H2 evolution on a virus scaffold
photovoltaics = yes
submit = Submit

name = Victor I. Klimov
affiliation = Los Alamos National Laboratory
address = MS-J567
phone = (505) 665-8284
fax = (505) 667-0440
email = klimov@lanl.gov
hompage = 
title = Fundamental Physics of Multiexcitons in Semiconductor Nanocrystals from the Prospective of Solar Energy Conversion
abstract = Recently, we demonstrated that PbSe nanocrystal quantum dots can efficiently produce multiple electron-hole pairs (excitons) in response to a single absorbed photon (Schaller & Klimov, Phys. Rev. Lett. 92, 186601, 2004). To address the generality of this carrier-multiplication phenomenon to other materials, we perform a comparative study of multiexciton generation in PbSe and CdSe nanocrystals that have distinctly different electronic structures. We find that both materials exhibit high-efficiency carrier multiplication and, as expected from simple effective-mass arguments, the activation threshold for this phenomenon is lower in CdSe nanocrystals than in PbSe nanocrystals (ca. 2.5 vs. 2.9 energy gaps). Interestingly, the efficiencies of multiexciton generation are nearly identical for both materials despite a vast difference in both energy structures and carrier relaxation behaviors, strongly suggesting that this phenomenon is general to quantum-confined semiconductor nanocrystals. Further, to study the mechanism for carrier multiplication we perform detailed analysis of ultrafast buildup dynamics of multiexciton populations in CdSe and PbSe nanocrystals (Schaller, Agranovich & Klimov, Nat. Phys. 2005). We observe that the generation of multiexcitons occurs on extremely short, sub-200 femtosecond time scales, and appears to be an instantaneous event. To explain this result, we propose a new model, in which direct (instantaneous) photo-generation of multiexcitons occurs via virtual single-exciton states. This process relies on confinement-enhanced Coulomb coupling between single excitons and multiexcitons and also takes advantage of a large spectral density of high-energy single- and multiexciton resonances in nanosized semiconductor crystals.
presentation = 
homepage = http://quantumdot.lanl.gov
technologyresults = 1. High-efficiency carrier multiplication in nanocrystals for applications in solar-electricity and solar-fuel producing technologies.
 
2. High-efficiency color conversion via nonradiative energy transfer for solid-state lighting applications.
 
relevantpapers = 1. R. D. Schaller and V. I. Klimov, High efficiency carrier multiplication in PbSe nanocrystlas: Implications for solar-energy conversion, Phys. Rev. Lett. 92, 186601 (2004).
 
2. M. Achermann, M. A. Petruska, S. Kos, D. Smith, D. D. Koleske, and V. I. Klimov, Energy-transfer pumping of semiconductor nanocrystals via nonradiative energy transfer using a quantum well, Nature  429, 642 (2004).
 
comments = The observed phenomenon of high-efficiency carrier multiplication has the potential to dramatically increase the performance of photovoltaic cells and can greatly advance solar-fuel producing technologies. Specifically, based on measured spectral dependence of multiexciton production, carrier multiplication can produce power conversion efficiencies of 65% in a single gap (low cost) device, which is almost 50% higher than the Shockley-Queisser limit calculated under an assumption that one photon produces one exciton. In addition to photovoltaic technologies, the observed phenomenon can find a wide rage of other applications ranging from high-efficiency splitting of water molecules to low-threshold lasing and generation of entangled photon pairs.
photovoltaics = yes
submit = Submit