Development of organic solar cells

The flexible solar module is as small as the page of a book.

Organic Solar Cells:Electricity From A Thin Film
Teams of researchers all over the world are working on the development of organic solar cells. Organic solar cells have good prospects for the future: They can be laid onto thin films, which makes them cheap to produce.
Established printing technologies should be employed for their production of the future. In order to achieve this goal of suitable solar cell architecture as well a coating materials and substrates have to be developed. “This method permits a high throughput, so the greatest cost is that of materials,” says Michael Niggemann, a researcher at ISE.

Nevertheless, organic solar cells are not intended to compete with classic silicon cells – they are not nearly efficient enough to do that just yet. Because they are flexible, however, they can open up new fields of application: Plastic solar cells could supply the power for small mobile devices such as MP3 players or electronic ski passes. Another possibility would be to combine solar cells, sensors and electronic circuits on a small strip of plastic to form a self-sufficient power microsystem.

At nano tech in Tokyo, the Fraunhofer experts will be presenting a flexible solar module that is as small as the page of a book. It was produced by a method that can easily be transferred to roll-to-roll technology – a vital step en route to mass production.

A new design principle helps to save costs, too: Until now, the front electrode, the one that faces the sun, has usually been made of expensive indium tin oxide because this material is transparent. But now there is an alternative: The Fraunhofer crew has interconnected a poorly conductive transparent polymer electrode with a highly conductive metal layer on the rear side of the solar cell. This connection is done trough numerous tiny holes in the solar cell .This has the advantage that a low-priced material can be used. The idea has already been patented.

The Fraunhofer Institute for Solar Energy Systems ISE in Freiburg is presenting avenues towards industrial mass production at the world’s largest trade fair for nanotechnology, the nano tech 2008 from February 21 through 23 in Tokyo.


Thin-layer Solar Cells May Bring Cheaper Green Power

Scientists are researching new ways of harnessing the sun's rays which could eventually make it cheaper for people to use solar energy to power their homes.
The experts at Durham University are developing light-absorbing materials for use in the production of thin-layer solar photovoltaic (PV) cells which are used to convert light energy into electricity.

The four-year project involves experiments on a range of different materials that would be less expensive and more sustainable to use in the manufacturing of solar panels.

Thicker silicon-based cells and compounds containing indium, a rare and expensive metal, are more commonly used to make solar panels today.

The research, funded by the Engineering and Physical Sciences Research Council (EPSRC) SUPERGEN Initiative, focuses on developing thin-layer PV cells using materials such as copper indium diselenide and cadmium telluride.

Right now the project is entering a new phase for the development of cheaper and more sustainable variants of these materials.

The Durham team is also working on manipulating the growth of the materials so they form a continuous structure which is essential for conducting the energy trapped by solar panels before it is turned into usable electricity. This will help improve the efficiency of the thin-layer PV cells.

It's hoped that the development of more affordable thin-film PV cells could lead to a reduction in the cost of solar panels for the domestic market and an increase in the use of solar power.

Solar power currently provides less than one hundredth of one percent of the UK's home energy needs.

The thin-layer PV cells would be used to make solar panels that could be fitted to roofs to help power homes with any surplus electricity being fed back to The National Grid.

This could lead to cheaper fuel bills and less reliance on burning fossil fuels as a way of helping to generate electricity.

Professor Ken Durose, Director of the Durham Centre for Renewable Energy, who is leading the research, said: "One of the main issues in solar energy is the cost of materials and we recognise that the cost of solar cells is slowing down their uptake.

"If solar panels were cheap enough so you could buy a system off the shelf that provided even a fraction of your power needs you would do it, but that product isn't there at the moment.

"The key indicator of cost effectiveness is how many pounds do you have to spend to get a watt of power out?

"If you can make solar panels more cheaply then you will have a winning product."

To aid its research the university has taken delivery of a £1.7 million suite of high powered electron microscopes, funded by the Science Research Investment Fund, which have nano-scale resolution allowing scientists to see the effects that currently limit the performance of solar cells.

One of the microscopes is the first of its kind in the UK and Professor Durose said: "This instrument will put the North East right out in front.

"We are working on new ideas in renewable energy and this opens up tremendous opportunities in research."