Solliance has achieved world record cell-level conversion efficiency of 13.5 percent and module-level aperture area conversion efficiency of 12.2 percent for perovskite-based photovoltaics using industrially-applicable, roll-to-roll (R2R) production processes.



Following the consortium's previous cell world record announced earlier this year, this latest breakthrough is another step towards the rapid introduction of this attractive, new type of efficient solar cell technology.

Perovskites promise high efficiency from relatively simple production processes, bringing the potential for cheaper, greener energy. Moreover, they can be processed into thin, lightweight and potentially semi-transparent modules for integration into windows or curved construction elements.

Solliance and its partners are helping to speed the market introduction of this technology by developing scalable, industrial processes for fabricating large-area modules. The goal is to enable seamless integration in a broad variety of new energy harvesting building blocks for infrastructure, building and vehicle construction and assembly.

In March this year, Solliance demonstrated R2R processes for both the electron transport and perovskite layers of the cells that make up such modules. Now, by further optimising and re-validating these processes on its dual R2R coating line, Solliance has improved performance at both the cell and module level.

After selecting two foil zones of each about 10 meters in length with a visual good perovskite quality, but with different R2R processing settings, 20 individual 0.1 cm2 solar cells were made in each zone. In one zone the maximum stabilised efficiency reached 13.5 percent (measured under maximum power point tracking conditions over 5 minutes) and in the second zone a maximum of 12.5 percent was reached. The average stabilised cell efficiency in the best performing zone was about 1 percent higher than the previously reported run in March 2017.

In addition, for each zone six 2 x 2 cm2 (or 4 cm2) aperture modules, four 3.5 x 3.5 cm2 (or 10.5 cm2) aperture modules and one 13 x 12.3 cm2 (or 160 cm2)aperture module were produced by implementing a P1P2P3 laser scribe process with 100 percent yield over all 22 fabricated modules. For the modules prepared from the best performing zone, the smaller modules of 4 cm2 showed a maximum aperture stabilised efficiency of 12.1 percent, with an average of 11.1 percent across the six modules.

The larger modules of 10.5 cm2 achieved a maximum aperture stabilised efficiency of 12.2 percent with an average of 11.0 percent across the four modules. And last but not least, the large module of 160 cm2) see picture) achieved an aperture stabilised efficiency of 10.1 percent.

All processing steps used low-cost materials and scalable processes at temperatures below 120degC. This highlights the potential for cost-effective, high-volume production of perovskite solar cells.

"These results show that the developed R2R process is very reproducible over different runs in time, which is very important for future reliable manufacturability", explains Pim Groen, professor of SMART materials at the Technical University of Delft and program manager at Holst Centre/Solliance.

Richard Caldwell, managing director of Greatcell Solar remarked: "The metals project at Solliance is hitting its targets. The successful translation of this PSC technology from the laboratory to the factory will open up massive commercial opportunities. A particularly pleasing feature of the current progress is the possibility to solar enable commercial and industrial roofing using low-cost R2R processes, thus opening up a whole new space to capture the Sun's energy, all day, every day."

Perovskites have delivered incredible efficiencies in lab-scale photovoltaic cells. The challenge now is to upscale perovskite cells to larger modules with high efficiency and long lifetime at low cost. This demonstration of scalable roll-to-roll and sheet-to-sheet processes for the deposition of active layers and cell interconnections shows Solliance is excellently placed to realise this upscaling.

"We are confident of quickly boosting efficiencies above 15 percent for modules up to 30x30 cm2. And our research shows that optimising materials and processes is steadily improving the stability of perovskite devices under real life operational conditions," explains Ronn Andriessen, program director at Solliance.

Solliance is a cross-border Dutch-Flemish-German thin-film photovoltaics research initiative. Its research on the development and applications of perovskite-based PV modules is carried out in conjunction with industrial partners Greatcell Solar Limited, Solartek and Panasonic.