The EMPA team which set its fourth world record for thin film CIGS efficiency with an 18.7% efficient cell in May 2011 has done it again by notching a Fraunhofer Institute-accredited 20.4% efficiency cell.
"We have now finally managed to close the ‘efficiency gap’ to solar cells based on polycrystalline silicon wafers or CIGS thin film cells on glass", said team leader Ayodhya Tiwari.
The development was made thanks to the work of PhD students Adrian Chirila and Fabian Pianezzi with the EMPA team modifying the properties of the CIGS layer, grown at low temperatures, which absorbs light and contributes to the photo-current in solar cells.
The record-breaking flexible polymer cell surpasses the 20.3% benchmark set by thin film CIGS mounted on a glass substrate and with the polymer substrate permitting roll-to-roll continuous production of the cells, offers a clear cost advantage in production over traditional polysilicon wafer-based cells.
The next step for the EMPA team, which set efficiency records of 12.8% in 1999, 14.1% in 2005 and 17.6% in 2010, is to put their record-breaking cell into full production and EMPA has joined forces with startup Flisom with that aim in mind.
The EMPA research has been supported by the Swiss National Science Foundation (SNSF), the Commission for Technology and Innovation (CTI), the Swiss Federal Office of Energy (SFOE) and the EU Framework Programmes.
More information on the current market situation as well as future possibilities for Thin Film Technology can be obtained at the Thin Film Week 2013, April 16-18, 2013, in Berlin Germany.