Pushing the
Frontiers of
Solar Tech
A new center at the Massachusetts Institute of Technology (U.S.A.) is
dedicated to developing solar technologies that push the envelope in efficiency.
The Eni–MIT Solar Frontiers Center,
which formally opened in May, provides
researchers with resources for investigating the electronic nature and nanostructure of new devices. It brings together
research on photovoltaics that use quantum dots and new
deposition methods,
bio-inspired hydrogen
production methods
and more effective
solar thermal collectors. The alliance
between Eni S.p.A
and MIT for the next
five years involves a
financial commitment
from Eni for $50 million, equally distributed between the Solar
Frontiers program and
the MIT Energy Initiative.
At the center’s opening, Paolo Scaroni,
chief executive officer of Eni, said that
An LED light bulb incorporates a thin
film of quantum dots, which shape its
emission spectrum.
his company
foresees the
end of hydrocarbon use for
energy. The
company wants
to support solar
energy but finds
current technology is inefficient
and expensive.
The lab is doing things differently:
Since the alliance between Eni and MIT
began in February 2008, significant
research has included construction of an
ultra-flexible solar cell; advances in the
production of virus-based metal contacts
for solar cells; development of solar cells
that mimic the photosynthetic process;
and progress in understanding how photosynthesis splits water molecules.
There are two shared labs at the center:
one for activity characterization (
including an 100-fs-pulse Ti:sapphire laser) and
another for duration tests and realization phases. In addition to funding from
Eni, the center receives money from U.S.
National Science Foundation grants—
including $2 million for equipment.
Karen Gleason’s group demonstrated
a solar cell deposited on paper. They
first used oxidative chemical vapor
Nexxus
Pablo Benítez et al., Universidad Politécnica de Madrid and LPI
deposition to make 100-nm-thick
polymer electrodes, then deposited the
organic photovoltaic layer on top. After
multiple foldings, the device maintains
its initial performance. New deposition
methods are being developed to fabricate solvent-free polymer thin films.
These, combined with inorganic materials, may create efficient and environmentally stable photovoltaics.
During a lab tour, Vladimir Bulovic,
science director of the Eni-MIT Solar
Frontiers Center, showed off solutions of
colloidal quantum dots, bits of silicon
roughly 5 nm in diameter. The dots were
excited by ultraviolet light and emitted
at different colors in the visible, depending on size. This ability to manipulate
the absorption and emission spectra
of quantum dots is could be useful for
photovoltaic cells.
Bulovic also showed an LED light
bulb, which incorporates a thin film
of quantum dots. The bulbs, sold by
Nexxus Lighting, hit the market in June.
The brightness of an 8-W LED bulb was
comparable to a 75-W incandescent, and
the color quality was better.
Yvonne Carts-Powell ( yvonne@nasw.org) is a
freelance science writer who specializes in optics
and photonics.
