Photosynthesis is the natural process used by nature (plants) to convert solar energy into a
different form of energy containing nutrients like sugar, which are important for life. This
is probably the first process people tried to reproduce in order to convert solar energy into
electricity. Indeed, in 1839 A.E. Becquerel observes a small voltage developing across two
electrodes, dipped in a certain solution, when they were exposed to sunlight.We now explore
the same phenomenon using "the nanocrystalline dye solar cell" which is also called "organic
solar cell", or after the inventor, "Grätzel cell". This new type of solar cell partly
bypasses the photosynthesis and makes a shortcut conversion into electrical current.
This is called photo-voltaic power generation.
The inner part of this solar cell consists of molecules similar to chlorophyl, the same dye
which is present in green leaves. When it comes to direct conversion of sunlight into electricity,
however, it is better to use other dyes. Professor Grätzel has developed a synthetic dye which
is able to convert a large part of the sunlight into electrical current. Apart from the
synthetic dyes natural dyes such as chlorophyl, can also do the job. The best natural dyes
presently known are the anthocyanates. Anthocyanates are the purple-red dyes found in for
example black berries, rasp-berries, hibiscus leaves and blackcurrant. In this workshop
we will show how to build a solar cell with "kitchen table" tools. We will use basic
ingredients and items provided by Man Solar, a company that has developed solar cells
made of the cheapest components. Students will be able to test their cells and compare
the effects of different common dyes of the cell efficiency. The preparation steps of
the solar cells will be first shown on a screen. Students will then be able to build
their own solar cell, following the steps which will be handed out during the presentation.
They will learn that a solar cell can be built with the aid of hibiscus leaves, black berry
juice or black currant, "toothpaste titanium dioxide", a pencil, a little bit of iodine
and electrically conductive glass. The preparation steps will include: boiling water to
prepare dyes (similar to preparing tea); creating a conductive layer using a pencil;
assembling the cells using paper clips.
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Dr. Gaspari holds an undergraduate degree in Physics from the University of Bologna,
(Italy), and a M.Sc. and Ph. D. in Physics from the University of Toronto (Canada).
Following 10 years as senior Research Associate at the Semiconductor and Photovoltaics lab at
the University of Toronto, he is now an Associate Professor of Physics at UOIT.
Dr. Gaspari has over 80 publications in refereed journals and conference proceedings and has
received significant funding for his research from NSERC, CFI, OCE and several industrial
partners. His research interests are: emerging nano-crystalline materials for application
in the fields of renewable sustainable energy; third generation solar cells; thin film amorphous
silicon, diamond-like carbon and carbon nanotubes.
Dr. Gaspari is currently conducting research related to the characterization of the properties
and processing of photo-catalytic oxide nanomaterials, and the investigation and optimization
of the integration schemes of optical energy sources with photo-catalytic reactors, i.e.,
systems that make use of the absorption of light for applications to environmental cleanup
and water splitting for hydrogen fuel production. He is a co-investigator in the international
project "PhotoCathalytic Systems for Clean Energy and Environmental Applications" (PHOCSCLEEN),
sponsored by the European community and conducted in partnership with the Polytechnic Institute
of Turin (POLITO, Italy), the Universidad Nacional Autonoma de Mexico (UNAM, Mexico),
and the Université de Picardie Jules Verne (UPJV, France).
Dr. Gaspari current studies in Photovoltaics include the characterization of Dye Sensitized
Solar Cells, which use a similar process to that employed in the proposed system and will be
the focus of the presentation.
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