Helianthos
# Helianthos

On 8 September 2011 Nuon announced the pilot plant would be closed down since no investor for production expansion could be found. However, on 7 May 2012 Nuon announced that Helianthos has been sold to HyET Solar.

## 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 are fabricated that can substantially reduce the per-kilowatt hour costs of solar electricity. Further, the resulting photovoltaic laminates are lightweight, rugged and offer certain freedoms 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
* Portable applications.

## Sources

* Nuon Helianthos
