Traditional solar cells are made of semi-conductors such as crystalline
silicon. When light strikes the cell some of the energy is absorbed and
knocks electrons loose in the silicon which can be forced into a current and
drawn off for external use.
The new technology use small organic molecules as semi conductors which can be
dissolved in a solution and printed in any shape using a 3D printer.
Most photovoltaics work best in strong, direct, sunlight of an intensity that
is rarely seen in northern European countries.
But intriguingly the new material – known as organic photovoltaic – works more
efficiently when out of direct sunlight, so is well suited for Britain’s
Scientists discovered that when testing it in direct sunlight desert
conditions it could only manage 10 per cent efficiency, but in cloudy
conditions that jumped to 13 per cent.
Dr Fernando Castro, principal research scientists at the National Physical
Laboratory in Teddington, said: “Organic photovoltaics work much better in
low and diffused light conditions. Even if it’s cloudy they still work.
“It’s not that they are going to produce more power but they are more
efficient at generating power from the light that is available. So they
would work better than normal soar cells do in cloud.”
The material would be cheaper and more environmentally friendly than
traditional solar cells, slashing the cost of installing them on homes.
“In the short term it will be used for consumer electronics that you could
carry in your bag to charge your phone for example,” said Dr Castro.
“And it comes in a variety of colours and shapes, rather than the typical
black. It can even be transparent so you could put it on windows and you
wouldn’t see it.
“It’s very light so you could just roll it out onto a roof. You wouldn’t need
to reinforce the roof and there wouldn’t be any need for health and safety
“Companies are looking at putting it on the roof of the cars so that you
wouldn’t drain the battery with modern electronics like Bluetooth which are
on all the time.”
Researchers demonstrate how quickly Organic PV can be fitted
Although organic photovoltaics currently only produce around half of the
voltage of silicon solar panels, the team is confident that it will improve
within a few years.
They believe that within five years products using organic photovoltaics will
be widely available.
However the finding that the material worked better in clouds was so
counterintuitive that scientists have struggled to get funding to develop
the new technology because current standards are based on how well the
materials work in direct sunlight.
“Organic PV, which could offer greater efficiency in Britain’s gloomy skies,
may appear less efficient based on standardised lab testing,” said Dr
“For a long time this technology received little attention and limited push
from investors. We would definitely be further on if people realised this
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