ITO-free designs could be product of choice for organic solar cell developers

Dan Rogers - 02 Feb 2010

A European project is aiming to prove that the production cost of organic photovoltaics (OPV) can be significantly reduced, by creating indium tin oxide (ITO)-free alternatives.

Over the next three years, the Hiflex project will develop roll-to-roll OPV production for devices that do not employ the ITO film used in many current designs.

ITO is used as an anode or transparent conductive layer in OPVs but, due to the material cost and concerns about future indium supplies, the Hiflex project will try to create an alternative design that could drastically reduce the production costs for OPV modules.

Mobile electronics

The result could be wider applications of OPVs in mobile charging applications for mobile phones, laptops and mp3 players, says project coordinator Jan Kroon, programme coordinator for organic thin-film PVs at the Energy Research Centre of the Netherlands.

He comments: 'Konarka's already doing this [in commercial deals for OPV-based accessories] but these first products are based on ITO. If we are to be successful, we need to show that mechanical flexibility can improve and provide alternatives that are better than the ITO benchmark.'

The project will establish collaborations with end users in 2011, at the halfway point for the project.

Kroon explains: 'We don't have any real end users in the consortium at this stage, but that is something that certainly has our attention. We'll get in contact with stakeholders and define a few case studies.'

The case studies will produce OPV chargers for mobile devices using the roll-to-roll technology of partners such as the Holst Centre in the Netherlands and the Risø National Laboratory for Sustainable Energy, Denmark.

Cheaper devices

Despite Konarka and G24 Innovations (G24i) already finding markets for their solar cells in accessories, Kroon suggests that wider adoption will be more likely if cells can be manufactured at the low costs promised by industry, thus significantly undercutting thin-film silicon technologies.

He adds: 'OPV is considered a low-cost option that should finally be produced at around €50 per square metre. However, at present prices that it is impossible, as the ITO foil often used is a very expensive one. It is very important to replace that with something that is much cheaper.'

By the time the project ends in December 2012, the markets for OPVs may have been expanded by the likes of Konarka and G24i. Kroon hopes that the introduction of a low-cost and ITO-free material at this stage could encourage adoption by these OPV producers and make an immediate commercial impact.

He says: 'If we can prove that we can make ITO-free modules then we can interest companies like Konarka, and also get new companies on board.'

And a lower-cost technology could also interest companies currently uninvolved in the developing OPV markets.

Kroon states: 'We hope that more traditional PV companies will become interested in OPVs if we make sufficient progress in efficiency and lifetime.'