Hi everybody,
There are three photovoltaics talks at MIT tomorrow which may be of interest
to people.
Best
Johannes
1) Organic and Dye Sensitized Solar Cells
Michael McGehee
Associate Professor of Materials Science and Engineering and Director of the
Center for Advanced Molecular Photovoltaics, Stanford University Tuesday,
March 8
4:15 PM
Room 66-110
Organic solar cells and dye sensitized solar cells are very promising
because they can be deposited rapidly in roll-to-roll coating machines
without expensive vacuum chambers or high temperature processing. Since they
can be lightweight and flexible, it may soon be possible to roll them onto
rooftops at a cost several times lower than is now possible with silicon or
cadmium telluride solar cells. Since organic semiconductors do not contain
any rare or toxic elements, such as indium, cadmium or tellurium, organic
solar cells could be used to provide the world with a significant fraction
of its electricity.
My research group has used synchrotron x-ray diffraction and other
characterization techniques to reveal in detail how semiconducting polymer
chains and fullerene molecules pack in solar cells and shown how this
packing influences the electronic processes that determine how well solar
cells work. We have also measured the lifetime of polymer solar cells and
found it to be as high as 7 years.
We have also pioneered the use of long range Forster energy transfer to
improve light absorption in solar cells. We believe that the incorporation
of energy relay dyes into dye sensitized solar cells (DSCs) is going to make
it possible to raise their efficiency from 11 to 15% in the next few years
by extending the region of the spectrum that the cells can absorb farther
out into the infrared, where almost half of the sun's energy is located.
One of the great challenges to making highly efficient solar cells with
solution deposited films that have high defect densities is keeping the
films thin so the charge carriers can be collected before recombination
occurs while at the same time absorbing all of the light. We have recently
demonstrated that absorption and power conversion efficiency can be
increased by as much as 20% simply by nanoimprinting an array of domes into
the active layer before depositing a silver electrode so that incoming light
can be coupled into plasmonic modes that travel in the plane of the solar
cell.
Michael D. McGehee is an Associate Professor in the Materials Science and
Engineering Department and Director of the Center for Advanced Molecular
Photovoltaics at Stanford University. His research interests are patterning
materials at the nanometer length scale, semiconducting polymers, large area
electronics and renewable energy. He has taught courses on nanotechnology,
organic semiconductors, polymer science and solar cells. He received his
undergraduate degree in physics from Princeton University and his PhD degree
in Materials Science from the University of California at Santa Barbara,
where he did research on polymer lasers in the lab of Nobel Laureate Alan
Heeger. He did postdoctoral research with Galen Stucky and Brad Chmelka at
the University of California at Santa Barbara on the self-assembly of
organic-inorganic mesostructures. He has won the 2007 Materials Research
Society Outstanding Young Investigator Award and the Mohr Davidow Innovators
Award.
2) "CONTROL OF LIGHT-MATTER INTERACTION USING DISPERSION ENGINEERED PHOTONIC
STRUCTURES"
Vinod M Menon, Queens College of CUNY
Tuesday, March 8, 2011, 3:00 PM
RLE Conference Room: 36-428
Coherent interaction of an ensemble of dipole active atoms or excitons with
vacuum electromagnetic field has been studied extensively since its initial
conception by Dicke in 1954. However, when the emitters are not only
periodically arranged, but are also placed in a periodically modulated
dielectric environment, the interaction between them is carried by the
electromagnetic Bloch waves of the photonic crystal. This coherent
interaction results in the formation of strongly coupled light-matter
quasiparticles called Bloch polaritons. In this talk I will discuss our
recent work demonstrating the formation of such quasiparticles in a
periodically arranged multiple quantum well system. Tuning of these
polariton states using electric field and its application for switching and
slow light enhanced nonlinear optics will also be discussed. Following this
I will discuss our recent work on dispersion engineered metamaterials for
controlling the spontaneous emission rate of quantum dots. Unlike
microcavity structures that rely on localization of electromagnetic field
for increase in the photon density of states, the present work exploits the
flat dispersion in anisotropic materials to create more states for the
emitter to emit through. Finally I will briefly discuss our work on
nonreciprocal optical elements realized using quasiperiodic photonic
crystals embedded with colloidal quantum dots.
Dr. Vinod. M. Menon is an Associate Professor of Physics at Queens College
and Graduate Center of the City University of New York (CUNY). He joined
CUNY as part of the Photonic Initiative in 2004. Prior to joining CUNY he
was a research staff member at Princeton University (2003-04). He joined
Princeton as the Lucent Bell Labs Post Doctoral Fellow in Photonics in 2001.
He received his MSc in Physics from the University of Hyderabad, India in
1995 and his Ph.D. in Physics from the University of Massachusetts in 2001.
His current research interests include the development of classical and
non-classical light sources using quantum dots, metamaterials for
controlling light-matter interaction, and engineered nonlinear optical
materials using hybrid nanocomposites.
3) Prof. Sheila Kennedy's lecture on PV Design applications
March 08, 2011 12:00p-1:00p
Location: 56-167
Sheila Kennedy, MIT Professor of the Practice of Architecture, will present
design work that explores the new nexus of adaptable/responsive design, soft
ware, ?soft? solar materials and flexible electronics. This talk will focus
on the challenges and opportunities of accelerating the wide spread use of
organic thin film and generation 3 CIGs based solar cells. Drawing on the
intersection of material research from coursework at MIT and real-world
demonstration projects from her practice at KVA MATx,
www.kvarch.net Kennedy
will discuss how design innovation in architecture and building materials is
creating new form factors and applications for solar energy, changing the
configuration of public space in the built environment, and driving
innovation in the creative economy. Keywords: architecture, innovation,
flexible photovoltaics, flat to form manufacturing, craft and technical
hybrids, prototyping.
Speaker: MIT Faculty Profile: Sheila Kennedy, AIA
http://sap.mit.edu/resources/portfolio/kennedy/
With lunch.
-----------------------------------------------
Dr. Johannes Hachmann
Postdoctoral Fellow
Aspuru-Guzik Research Group
Harvard University
Department of Chemistry and Chemical Biology
12 Oxford St, Rm M104A
Cambridge, MA 02138
USA
eMail: jh(a)chemistry.harvard.edu
-----------------------------------------------
_______________________________________________
Aspuru-meetings-list mailing list
Aspuru-meetings-list(a)lists.fas.harvard.edu
http://lists.fas.harvard.edu/mailman/listinfo/aspuru-meetings-list