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Extremely Effective Thin-Film Solar Cells Are Made Possible by Massive Band Bending at the SnS Interface

In the context of technology, “SnS interface” could refer to several different things depending on the specific field or application.  Solar cells will be crucial in the world’s transition to renewable energy as the quest for carbon neutrality grows and as a concerning pattern of rising temperatures and natural disasters brought on by global warming continues.

Now, a research group has laid the path for achieving higher open-circuit voltage in tin sulfide (SnS) solar cells, thus realizing their latent potential as a thin-film solar material.

Compound semiconductors with high light absorption that are used in thin-film solar cells make them lighter and more affordable to build.

SnS is one such environmentally beneficial thin-film solar cell material because it doesn’t contain any rare or dangerous components. Yet in recent years, scientists have started to doubt this assumption because, despite more than 20 years of study, their conversion efficiency had only reached 5% because of a low open-circuit voltage.

In the near future, we hope to fabricate homojunction solar cells with high conversion efficiency.

Assistant Professor Issei Suzuki

The team from Tohoku University’s Institute of Interdisciplinary Research for Advanced Materials, led by Assistant Professor Issei Suzuki, successfully demonstrated a SnS interface that exhibited substantial band bending, which is required to achieve a greater open-circuit voltage.

“We used photoelectron spectroscopy to analyze the electronic structure of the interface where molybdenum oxide was deposited on a SnS single crystal,” said Suzuki. “We confirmed that the interface state achieved a high open-circuit voltage.”

This is not Suzuki’s first breakthrough in SnS thin-film solar cells either. He was in charge of another team that made the first n-type SnS thin film in history back in December 2021. This made it possible for thin film homojunctions to form.

In the current study, the team also put forth a technique for creating interfaces appropriate for SnS thin-film solar cells, which included lowering the sulfur deficiency in the SnS thin films and using a homojunction structure in both their n-type and p-type layers.

“In the near future, we hope to fabricate homojunction solar cells with high conversion efficiency,” added Suzuki.

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