Roll-to-roll flexible perovskite solar cells hit record efficiency

Technology News | March 10, 2017

By Nick Flaherty

Materials & processes Energy Harvesting

Solliance, a grouping of research centres and companies from Holland, Belgium and Germany with Solartek, Dyesol and Panasonic, has used an industrially-applicable roll-to-roll process for the production of these cells, paving the way to an accelerated market introduction.

Perovskite microcrystals are a promising material to make high-yielding, thin-film solar cells. They can be processed into thin, light-weight and potentially semitransparent modules that could eventually be integrated in building materials such as windows or curved construction elements. Solliance and its research partners focus on using scalable, industrial processes towards the fabrication of large-area modules, eventually suitable for seamless integration in a broad variety of PV systems.

The current world record efficiency of a small, lab scale perovskite-based PV cell is 22.1%, while other roll to roll technologies using organic dyes have reached 13%.

“The challenge is to upscale perovskite cells to larger size, industrially-manufacturable modules with high efficiency and long lifetime at low cost,” said Ronn Andriessen, Program Director at Solliance. “These 12.6% R2R up-scaled perovskite-based solar cells are a first and important step in this development. With this result, we are confident to quickly boost the up- scaled perovskite based PV module efficiency above 15% by using low cost materials and processes. Furthermore, we are working hard to improve the stability of these devices under real life operational conditions.”

The roll-to-roll (R2R) process was developed for both the electron transport and the perovskite layers on the new Solliance dual R2R coating line, as developed by Solliance with its partners VDL Enabling Technologies Group (VDL ETG), Smit Thermal Solutions and Bosch-Rexroth. The in-line roll-to-roll coating, drying and annealing processes were executed at a linear speed of 5 m/min on a 30-cm wide commercial PET/ITO foil and under ambient conditions. After applying a newly developed off-line single device finishing step, individual solar cells of 0.1cm² achieved efficiencies of up to 12,6%, measured under maximum power point tracking conditions during 5 minutes. All process steps on this roll-to-roll line were performed using low cost materials whilst keeping the process temperatures below 120 0C. This shows the high volume production potential of this new emerging thin film PV technology.

Next: R2R processing

“The demonstration of R2R processing at 5 m/min of perovskite layers for solar cells indicates that high- volume production, and hence with an expected very low cost, will be possible in the future”, said Pim Groen, Professor of SMART materials at the Technical University of Delft and Program Manager at Holst Centre/Solliance. ”These results show that the Solliance research partners, with their in depth know-how on processing of thin film PV devices and their extensive sheet-to-sheet and roll-to-roll pilot production infrastructure, are excellently placed to realize this upscaling.”

VDL ETG has been leading the consortium of equipment manufacturing companies that designed and built the R2R coating line which uses dye from Dysol in Australia. “Dyesol is very pleased with this breakthrough; we are committed to developing the industry standard for R2R Perovskite Solar Cell (PSC) PV manufacturing in conjunction with Solliance and this result is an important step along this route,” said Richard Caldwell, Managing Directo of Dyesol. “This pioneering work confirms that Dyesol and its partners retain a global leadership position in the industrialisation of PSC Technology, and in particular, its continuous R2R processing for flexible BIPV applications – a core element of its commercialisation strategy.”Flexible thin-film perovskite PV technology can be seamlessly integrated in building elements, on curved surfaces and can be made semitransparent. Combining the industrially-applicable manufacturing processes with Solliance’s proprietary back-end interconnection process allows the creation of perovskite-based PV modules with any form and shape and any desired current-voltage output.

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