Italian and Iranian researchers have developed the new “deposition via an antisolvent-soaked applicator” technique, which they describe as an easily scalable process to produce uniform, pinhole-free perovskite films. They tested the process on a 6.7%-efficient solar cell based on a polyethylene terephthalate substrate, raising its power conversion efficiency by 82%.

Researchers from the University of Rome Tor Vergata in Italy and the University of Zanjan in Iran have developed a new method to manufacture perovskite photovoltaic cells with just a small sheet of paper as an applicator. They claim that this eliminates the need for a spin coater or other large-area techniques such as slot-die coating or blade coating.

“This method enables the deposition of the perovskite film incredibly cheaply as well as effectively,” researcher Nazila Zarabinia told pv magazine. “The trick to achieving good solar cell efficiency is to soak the piece of paper in an anti-solvent before drawing the applicator over the precursor liquid.”

They said the novel applicator has better porosity and smoothness than other soft applicators for the deposition of high-quality perovskite films. They described the “deposition via an antisolvent soaked applicator (DASSA)” technique as an easily scalable process to produce uniform, pinhole-free perovskite films.

“We think this simple method will appeal to all those labs setting up a line in perovskite research who have not been able, for money or time, to buy expensive deposition equipment since it enables the deposition of the perovskite film incredibly cheaply,” researcher Thomas Brown explained. “It can also be of particular interest to groups developing automated printing techniques by applying the anti-solvent, not on the perovskite film as usual, but on the applicator instead.”

Deposition via the DASSA method

Image: University of Rome Tor Vergata

The research group tested the process on a solar cell based on a polyethylene terephthalate (PET) substrate with a power conversion efficiency (PCE) of 6.7%.

“When the paper applicator was soaked in the green antisolvent, ethyl acetate, the maximum PCE jumped to 11.1%,” the scientists said. “By soaking the applicator with antisolvent, double cation perovskite films with increased uniformity, crystallinity, and better-interconnection were obtained as evidenced by analysis of the PL, SEM, and XRD measurements.”

For comparison, a similar device developed with spin coating and an antisolvent method achieved an efficiency of 14.9 %. The researchers said that this shows there is scope for further improvement.

“Setting up an automated system that would carry out the application more precisely compared to the manual deposition we implemented here would improve macroscopic and microscopic film uniformity as well as performance and reproducibility,” they said.

The researchers described the new manufacturing process in “Simple and effective deposition method for solar cell perovskite films using a sheet of paper,” which was recently published in iScience.