Helianthos

articleissues
expert=Energy development
refimprove=January 2007
peacock=October 2007
technical=October 2007

Helianthos is a program focused on the development of solar cell modules that can be manufactured via roll-to-roll processes on long foil substrates. Helianthos is run by a core group of industrial partners and is supported by universities, technology institutes, and other partners. Since 2006, Helianthos is a wholly owned subsidiary of Nuon, an energy company from the Netherlands.

Process Technology

The process uses a temporary substrate on which flexible thin film solar cells are deposited. The use of the temporary substrate allows relatively high processing temperatures while using (semi-)continuous roll-to-roll (or reel-to-reel) production processes and cost-efficient, abundantly available materials.

The active layers of such solar cells comprise a transparent conductive oxide layer (TCO), an active absorbent layer (e.g. thin film silicon), and a back contact layer (e.g. a reflective metal layer).

Process Sequence

The key steps in the process sequence are:
# Deposit the TCO layer on a temporary metal substrate foil using chemical vapor deposition (CVD) at about 500 °C (932 °F) .
# Deposit the active absorber layer (e.g. thin film silicon layer) using plasma enhanced CVD
# Deposit the reflective back contact by means of physical vapor deposition
# Pattern for monolithic interconnection
# Laminate to a permanent carrier foil
# Remove the temporary substrate foil by means of wet etching
# Confectioning, contact application and encapsulation

Applications

Using this process, flexible photovoltaic (PV) laminates will be fabricated that can substantially reduce the per-kilowatt hour costs of solar electricity. Further, the resulting photovoltaic laminates are lightweight, unbreakable, aesthethic, and offer freedom of design.

PV laminates have the potential to be used for a range of applications, including:
* Large area roofing and other large area applications to generate electricity
* Rural electrification
* Industrial applications
* Consumer applications, e.g. solar cells for portable applications.

Sources

* [http://www.nuon.com/about-nuon/Innovative-projects/helianthos.jsp"Nuon Helianthos"]

See also

* Solar cell

References

* [http://www.jointsolarpanel.nl/bernd%20stannowski%20zonnecellendag%20utrecht%202006-ok.pdf"Challenges in the development of thin-film silicon PV by Bernd Stannowski"]