JANUARY 15 - 16, 2015
LAWRENCE BERKELEY NATIONAL LABORATORY
BUILDING 50 AUDITORIUM
Abstract: The organizing theme of the Kavli Institute at Cornell for Nanoscale Science (KIC) is the creation of next-generation tools for imaging, manipulation, and control at the nanoscale. In this talk, I will present recent work from KIC members that illustrates the theme, ranging from atomic-scale images of the world’s thinnest pane of glass, to measurements of the spatial and spectral properties of correlated electron systems, to a song played on a nanotube guitar. We’ll see that new tools lead to new science, and also to many surprises.
Abstract: Organic PV diodes require a donor-acceptor heterojunction that can split a photogenerated exciton to an electron-hole pair. We have recently found that it is possible to measure the Coulomb energy set up as the electron-hole pair separate, through the modulation of the ground-state optical absorption of the donor caused by the local electric field set up between the electron and hole. We find a substantial electron-hole separation at very early times, setting up an electrostatic field energy of up to 200 meV in times as short as 40 fsecs. This substantial Coulomb energy requires that the electron and hole have fully separated, to at least 4 nm at the very earliest times, and we consider that this arises through direct electron transfer from donor to acceptor states that are delocalised over many acceptor molecules over distances of 4 nm or more.
Large spin exchange energies allow scope for multiple exciton generation for materials for which the triplet exciton energy is less than one half of the singlet exciton energy, since this favours energetically the fission of a photogenerated singlet to a pair of triplet excitons. If this process can be used in tandem with a lower energy gap semiconductor that harvests singlet excitons directly then this may enhance solar energy conversion beyond the single-junction Shockley-Queisser limit. We have found that this can be achieved using a pentacene/lead selenide hybrid solar cell device structure, for which triplet transfer from pentacene to PbSe occurs within 1ps.
Prof. Nai-Chang Yeh, Co-Director, Kavli Nanoscience Institute, California Institute of Technology; Professor of Physics, California Institute of Technoloy
"Current Nanoscience Research at Caltech on Quantum Frontiers, Bio & Medical Engineering, and Sustainability"
Abstract: The purpose of this talk is to provide an overview of representative nanoscience research activities at Caltech, particularly in the areas of quantum frontiers, bio- and medical engineering, and sustainability. The highlights to be discussed in quantum frontier research will include atomic and nano-scale investigations of novel quantum matter (e.g., unconventional superconductors and topological matter), and the development of quantum information technology based on light-matter interactions in nano-photonics and quantum optomechanical circuits. In the case of bio- & medical engineering, examples will be given on topics of DNA-based nano-fabrication technology, bio-molecular computation, and nanotechnology-enabled medical applications. For sustainability, topics to be covered will primarily focus on nano-engineering of materials for energy applications. Some examples will include: nano-fabrication of meta-materials for more efficient photovoltaic cells, nano-plasmonic assisted thermo-chemical cycling for efficient water splitting, and DNA-engineering of new cellulases for better biofuels.
Cees Dekker, Director, Kavli Institute of Nanoscience, Delft University of Technology; Professor of Physics, Delft University of Technology
"Nanopores and nanostructures for biophysics experiments from single molecules to bacteria"
1. DNA translocation through solid-state nanopores 
Solid-state nanopores have proven to be a surprisingly versatile probe for single-molecule analysis of DNA. I will describe some of our recent efforts to expand the capabilities of solid-state nanopores even further, in the direction of single-protein detection, graphene nanopores, plasmonic nanopores, and DNA origami nanopores.
2. Exploring biophysics of bacteria with nanofabricated shapes 
We shape bacteria into forms that deviate from their natural phenotype. Specifically, I will show our ability to shape live E. coli bacteria into novel shapes such as rectangles, squares, triangles and circles. We study pattern formation in these geometries. I will show spatiotemporal oscillations of Min proteins – associated with cell division – in such artificial geometries of live E. coli cells.
 C. Dekker, Solid-state nanopores, Nature Nanotechnol. 2, 209−215 (2007)
 F. Wu et al, submitted
Abstract: Through eons of evolution, nature has engineered extremely sophisticated nano-machines capable of performing amazing tasks in the cell. Some of these function cyclically, converting chemical energy into mechanical work, i.e., they operate as molecular motors. Working at energies not much higher than those of the thermal bath that surrounds them, these motors function as open thermodynamic systems, capable of exchanging both energy and matter with the environment. I will present various examples that we have been studying in our laboratory at the Kavli Institute, describe briefly their mode of operation, and point out some of the most interesting aspects that we are investigating such as the origin of their large thermodynamic efficiencies, how they coordinate their activities, and how energy flows at the nanoscale between the various parts of the motor and between the motor and the thermal bath.
Abstract: I will discuss energy conversion, transport channels, and circuitry for selected nanoscale systems. Of particular interest will be photon capture/conversion, custom-designed molecular machines, and phononics.
Abstract: Coming soon.
Abstract: Synthetic systems will be described in which molecules are linked into nanoscale compartments and used to enclose catalysts as a way to store, transform and use energy. This presentation will also show the use of metal-organic frameworks and inorganic nanoparticles in modulating rates of reactions and stabilization of intermediates of chemical reactions along diverse energy landscapes.
Abstract: Recent breakthroughs in the understanding of solar cells have led to new record efficiencies. Like all new scientific developments, there are repercussions that extend into new and unexpected areas. Serendipitously, the need for high internal reflectivity in the record-breaking solar cells has solved a 50-year-old-impasse that had prevented progress in thermo-photovoltaics. In thermo-photovoltaics, heat radiation is converted directly into electricity in photovoltaic cells; but the efficiency has not exceeded ~15%. By exploiting a black-body photon gas to recycle the thermal photons, efficiencies are projected to reach >50%, making thermo-photovoltaics competitive with mechanical heat engines to produce electricity. The only moving parts are photons. Nonetheless, a thermo-electric generator could possibly replace the internal combustion engine for charging hybrid vehicles.