I will now deal with the various PV technologies,
which depend on the kind of material used in the solar cell to
achieve the photon conversion.
You will see here the review of the solar cell technologies.
Most of the technology are based on non-organic
materials.The dominant technology based on
Belke Crystalline Silicon is
mention on the left with a typical cell thickness of
about two hundred or three hundred micrometer.
Thin films, typically one micro thick can also be used.
Silicon, Cadmium Telluride or Copper Indium Gallium Diselenide CIGS.
High efficiency solar cells based on
Belke three five Silicon Jack compounds are often combined with concentration.
Organic materials like polymers can be also used to prepare solar cells,
sometimes combined with silicon hybrid cells.
Let's review now these various technologies.
The Crystalline silicon technology is clearly dominant in the market.
Module efficiencies around twenty percent are now
available on the market at fast decreasing price.
As compared to competing technologies,
Crystalline Silicon is the most mature because
it takes advantage of the progress of the semiconductor industry.
Furthermore, Crystalline Silicon Cells are more efficient,
have a longer lifespan than thin-film cells.
However, we have to mention
some drawbacks such as a decrease of efficiency with raising temperatures.
More serious than in case of thin films or the cost of silver contacts.
In principle, thin film technologies are potentially cheaper because
they use about two orders of magnitude less raw material than Belke Crystalline Silicon.
However, the crystalline silicon cost is no where it is fastly dropping.
However the conversion efficiency is lower than silicon
slightly in case of cDte and CIGS.
Thin film silicon takes advantage of the mature industry of flat panel displays.
Thin film technologies are generally compatible with
cheap glass or flexible substrates polymers steel,
which can be a strong advantage.
In contrast, thin film technology can be limited by rare earth scarcity such as
indium extensively used in these technologies on toxicity in particular cadmium.
Organic materials can be extremely cheap.
However, the complete solar cell must be
restricted to organic materials to keep this advantage.
However the organic cells require
an efficient packaging in order to protect
the organic materials from [inaudible] are vapor and so on.
If inorganic thin film are used for packaging which is actually the case,
this promising economic advantage disappears.
Anyway, the conversion efficiency remains very low,
which balances obvious advantage of the polymer technologies.
The development of the organic technologies currently suffers with
a major problem such as instability on low conversion efficiency.
The recent evolution of the share of PV technology is shown here.
So, crystalline silicon technology remains clearly
dominant with about ninety percent of the world market.
The thin film technology appeared on the market
at the industrial level about ten years ago.
However, the market share does not appear to increase significantly.
The evolution of the best performances of
the values Solar Cell Technologies is shown here.
These best values are recorded in research laboratories generally on small area,
one centimeter square or even less.
The performances on commercial modules are found significantly lower.
Moreover, these values are recorded on cells as
prepared without taking care of stability.
This last remark has to be taken into account when considering
the performances of emerging technologies i orange such as organic or perovskite cells.
The thin film technology are displayed in
green significantly below Crystalline Silicon in blue.
The best PV solar efficiencies out in multi junctions based on
Sci Fi mono crystalline compounds with
an actual maximum of about forty five percent. Thank you.
Pr. Bernard DrevillonProfessor at Ecole polytechnique
Erik JohnsonCNRS Researcher
