A team of researchers led by Penn State University has created a new process to fabricate large perovskite devices that are more cost and time effective and holds the potential to accelerate future materials discovery.

EM-FAST, also known as spark plasma sintering, involves applying electric current and pressure to powders to create new materials. The process has a 100% yield wherein all the raw ingredients go into the final device, as opposed to 20 to 30% in solution-based processing.

The technique produced perovskite materials at .2 inches per minute, allowing scientists to quickly create large devices that maintained high performance in laboratory tests.

The team reported their findings in the journal Nature Communications.

“This method we developed allows us to easily create very large bulk samples within several minutes, rather than days or weeks using traditional methods,” said Luyao Zheng, a postdoctoral researcher in the Department of Materials Science at Penn State and lead author on the study.

The EM-FAST Technique

The researchers used a sintering method called the electrical and mechanical field-assisted sintering technique (EM-FAST) to create the devices.

Sintering is a commonly used process to compress fine powders into a solid mass of material using heat and pressure.

While these materials have excellent properties, the approach is expensive and inefficient for creating large perovskites and the solvents used may be toxic, the researchers said.

“Our technique is the best of both worlds…we get single-crystal-like properties, and we don’t have to worry about size limitations or any contamination or yield of toxic materials,” said Bed Poudel, a research professor at Penn State and a co-author.

Because it uses dry materials, the EM-FAST technique opens the door to include new dopants, ingredients added to tailor device properties, that are not compatible with the wet chemistry used to make thin films which in turn can potentially accelerate the discovery of new materials.

This opens up possibilities to design and develop new classes of materials, including better thermoelectric and solar materials, as well as X- and γ-ray detectors, the researchers said.

The new process also allows for layered materials — one powder underneath another — to create designer compositions. In the future, manufacturers could design specific devices and then directly print them from dry powders.

While the university scientists have long used EM-FAST to create thermoelectric devices, this work represents the first attempt to create perovskite materials with the technique.

Recently, an international team of researchers developed a new technique to enhance the durability of inverted perovskite solar cells, which can be an essential step toward commercializing emerging photovoltaic technology and significantly reducing the cost.

In January, researchers at the Helmholtz-Zentrum Berlin said that they had produced perovskite solar cells to achieve efficiencies of well above 24%, which are resistant to drop under rapid temperature fluctuations between -60 and +80 degrees Celsius over one hundred cycles.