Scientists in Germany's Karlsruhe Institute of Technology (KIT) have applied vapor-based deposition techniques and laser scribed interconnection (well established processes in existing thin-film solar manufacturing) to fabricate perovskite mini modules which achieved a maximum efficiency of 18% for a device measuring 4cmÂ².
The team believes that based on these processes, it would be possible to simplify processing and reduce losses associated with scaling up to commercial-sized devices.
Most of the highest-performing perovskite solar cells produced by researchers to date have been fabricated using spin coating, which is difficult to apply to larger surface areas. Other solution-based techniques such as inkjet printing, blade coating and slot-die coating have strong potential for low cost, high throughput manufacturing, but also tend to see high-performance losses as the device area increases. Researchers are investigating controlling these processes via additives to the precursor materials, but other routes could also be possible.
The scientists in this work investigated vapor-based deposition techniques for deposition of the cell layers, along with laser scribing for cell interconnections. The group claims its work represents the first time these two techniques have been investigated in combination for a perovskite PV module, and demonstrates rather positive results: a 4cmÂ² device that achieved 18% efficiency, and scaled up to 51cmÂ², reaching 16.6% efficiency.
'The comparison of the achieved upscaling losses of only 3.1% (relative efficiency)/dec of upscaled area with other upscaling approaches as well as established thin-film PV technologies like CIGS, c-Si, and CdTe highlights the excellent upscaling efficiency of the developed process,' says the group.
They note that while initial efficiencies for perovskite cells fabricated with vapor-based deposition are lower than for solution-based, the vapor processing has lower losses associated with the increase in area. Regarding the laser processed interconnections, the results were achieved using a 532 nanosecond laser already suitable and established for industrial use, while other studies have relied on much more expensive and complex short-duration lasers.