NSF Workshop:
Emerging Opportunities of Nanoscience to Energy Conversion and Storage
Section 6: BioNano Techniques for Energy
Applications
T.H. LaBean, D. Feldheim, H. Yan, T. Lin, N. Seeman
The State of Energy Usage.
The
following energy facts were taken from [Maugeri, Science, 2004, 304, 1114.].
The current global rate of energy
consumption is 400,000 PetaJoules per year, equal to 4 million nuclear bombs.
Twenty-five percent of that is consumed by the US, and eighty-five percent is
generated from fossil fuels. This leads to a total carbon output per year of 7
GigaTons (109 Tons), which is enough CO2 to fill Lake
Michigan every year. Global energy demand by the year 2050 will exceed 1
Million PetaJoules (1021 J), and the amount of CO2 in the
atmosphere will double, causing a global temperature rise of up to 4 ¼C.
Further calculations by major sources claim that current world oil reserves
equal 1 trillion barrels, and since the current global consumption rate is 28
billion barrels per year, we have a maximum of 35 years of oil remaining.
Alternative Sources of Energy.
Examination of the usual list of
alternative energy resources shows that we could potentially produce
approximately 150,000 PJ from biomass, 40,000 PJ from wind, 20,000 PJ from
hydroelectric. So allowing for growth in consumption, we would need something
like 250,000 PJ from nuclear, which could only be provided if one new power
plant is opened every 2 days until 2050. Instead, we must turn to alternative
methods for exploiting solar power. In fact, more energy is available from the
sun in one hour than we use in one year. Harvesting solar energy is a $7
Billion Industry that is growing at a rate of 32% per year. Besides active
(photovoltaic) solar energy harvesting and passive solar designs for lighting
and heating, we can finally follow the lead of visionary Jules Verne, who in
1874 commented, ÒWater will be the coal of the future.Ó
Photocatalytic Water Splitting
(Energy Storage)
Hydrogen Oxidation (Energy
Release)
Without catalysts these reactions
are useless!
New catalysts are needed to
produce and utilize alternative fuels. Catalyst design is exceedingly
difficult; catalyst discovery relies largely on serendipity. We now know that RNA can evolve in
response to selection pressures (magnetism) to catalyze the formation of
materials with a desired property. Can biomolecule evolution be used to
discover new catalysts for alternative energy and CO2 sequestration?
BioNano Assembly and Selection
Approaches.
Bionanomaterials can help on at least
two different fronts:
1). Nanofabrication of
photovoltaic, thermoelectric, and nanoelectronic materials by
biomolecule-guided self-assembly
2). Biomolecule-driven evolution
of inorganic catalysts for energy applications.
Bionanoassembly
makes use of biological inspiration and biomacromolecules for fabrication of
specific nanostructures via molecular recognition reactions. Assembly of a variety of nanoscale
materials into complex structures have been accomplished by programmable
assembly using DNA and viral particles.
Using DNA tile building blocks, objects have been created with sizes
between microns and millimeters and having feature resolution less than 5-10
nanometers. We hope to apply these
achievements to solve problems in photovoltaics, thermoelectrics,
nanophotonics, battery, fuel cell, and fuel conversion areas which would
benefit from the ability to organize nanomaterials into designed structures
with low nanometer resolution.
Directed
evolution of biomolecules capable of templating the deposition of diverse
inorganic materials into specific nanocrystalline forms holds great promise for
finding useful catalysts for a wide range of chemical reactions critical to
energy applications.
Current Nanopatterning
Methods.
Conventional
techniques for fabrication of nanostructures include electron-beam lithography
(EBL), dip-pen lithography (DPL), nanostamping, molecular beam epitaxy (MBE)
and vapor-liquid-solid (VLS) growth. These methods offer several positive
aspects for high-efficiency thermoelectric and nanoelectronic materials
fabrication.
EBL and DPL are extremely useful
for fabrication of complex two-dimensional nanoelectronic patterns, however
they are quite slow and limited to writing single copies or at best a fairly
small number of simultaneous copies. Through the ability to deposit single
atomic layers with high crystal quality, MBE and VLS are able to generate
quantum-confined nanostructures with high mobility, leading to high Seebeck
coefficient and high electrical conductivity (both of which are required for
high thermoelectric efficiency). Recent work in MBE quantum well superlattices
and self-organized MBE quantum dot superlattices (QDS) in the
Stranski-Krastanov growth mode have led to some of the best thermoelectric
materials to date [1,2], while VLS-grown nanowires show great promise for high
thermoelectric efficiency [3].
A
main course for future improvement in these methods will be to study the
mechanisms that lead to high thermoelectric figures-of-merit. As of now, a self-consistent
picture of electrical and thermal transport in quantum-confined nanostructures
(especially QDS nanocomposites) remains elusive. Current techniques for
creating QDS materials lead to arrays with random spacing and much variation in
dot size, making study of thermoelectric effects difficult. Pursuing these
mechanisms to further increase efficiency will likely require the fabrication
of regular, periodic arrays of quantum dots with consistent sizes and shapes
using techniques such as direct matrix seeding [4]. In this way, mechanisms
such as phonon band gaps [1], miniband formation [5], and acoustic phonon
scattering off of inclusions [6] can be precisely understood.
References
Maugeri,
Science, 2004, 304, 1114.
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.
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.
1R.
Venkatasubramanian, E. Siivola, T. Colpitts, and B. O'Quinn, "Thin-Film
Thermoelectric Devices with High Room-Temperature Figures of Merit", Nature 413, 597 (2001).
2T.C.
Harman, P.J. Taylor, M.P. Walsh, and B.E. LaForge, "Quantum Dot
Superlattice Thermoelectric Materials and Devices", Science 297, 2229 (2002).
3Y.M.
Lin and M.S. Dresselhaus, "Thermoelectric Properties of Superlattice
Nanowires", Physical Review B
68, 075304 (2003) and
references therein.
4X.
Weng, W. Ye, S.J. Clarke, R.S. Goldman, V. Rotberg, A. Daniel, and R. Clarke,
"Matrix-Seeded Growth of Nitride Semiconductor Nanostructures Using Ion
Beams", Journal of Applied Physics 97,
064301 (2005).
5A.A.
Balandin and O.L. Lazarenkova, "Mechanism for Thermoelectric
Figure-of-Merit Enhancement in Regimented Quantum Dot Superlattices", Appl.
Phys. Lett. 82, 415 (2003).
6J.M.
Zide, D.O. Klenov, S. Stemmer, A.C. Gossard, G. Zeng, J.E. Bowers, D. Vashaee,
and A. Shakouri, "Thermoelectric Power Factor in Semiconductors with
Buried Epitaxial Semimetallic Nanoparticles", Applied Physics Letters 87, (2005).