The team’s roll-to-roll coated device uses carbon electrodes rather than gold, making printable solar cells more affordable. (Image Credit: Swansea University)
Engineers from the SPECIFIC Innovation and Knowledge Centre at Swansea University say they have successfully created printable versatile solar cells via slot die coating in a roll-to-roll process. Making this mainstream would then allow people to charge their devices from the sun using these flexible solar cells.
The team used carbon electrode ink rather than gold electrode, which is more expensive and takes longer to apply on solar cells after printing. Carbon electrodes can be applied continuously during printing. This process is more affordable and quicker. “The key was identifying the right solvent mix, one which dries as a film without dissolving the underlying layer,” Dr. David Beynon, Senior Research Officer from the SPECIFIC, said. “X-ray diffraction analysis showed carbon electrode ink is capable of this when formulated with an orthogonal solvent system. This innovative layer can be applied continuously and compatibly with the underlying layers at a low temperature and high speed.”
“Perovskite solar cells show great promise in the drive towards cleaner, greener energy. The ability to produce a fully working device entirely in-line makes high-volume manufacturing easier and more economical and is a big step towards their [commercialization]. It unlocks the idea of [a] manufacturing process where a solar ink is added one end and a solar cell emerges from the other,” Photovoltaic Research Lead Professor Trystan Watson said.
Devices that have carbon electrodes charge similarly to those with gold electrodes and achieve 13-15% power conversion efficiencies (PCE) while performing better at higher temperatures. It also provides long-term stability. The team’s R2R-coated device, printed on a 20-meter-long substrate, generated a 10.8% PCE.
“The most important part of this project was coating the carbon entirely, R2R, a new process of working with perovskite photovoltaics, which helps to scale up easier. For a few years now, the efficiency of these devices has been increasing, with the expectation that they could be fully printed. This work has proved that.” Dr. Ershad Parvazian, Postdoctoral Researcher at SPECIFIC, said.
Now the team needs to prove these printed PVs work as intended. “In order to achieve this, we need to start making something that really looks like a solar panel. We can then install them on buildings and understand how close we are to delivering on the promise of UK-based manufacturing of green renewables,” says Watson.
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