Physics and Astronomy news

Left to right: actual rocks which were used and the inks they produced, a nanosheet produced from the inks and a nanosheet showing atoms that make up the surface.

Dr Conor Boland

A team of researchers from the School of Mathematical and Physical Sciences have made a ground-breaking discovery, uncovering a previously dismissed family of nanomaterials than can be isolated from ordinary rocks.

The Sussex team, led by Dr Conor Boland, investigated isolating nanosheets on a large scale from common mica and chlorite minerals, finding that they possessed unusual properties that had been misunderstood due to previously applied methods.

“We literary bought them from a geology store and they arrived covered in dirt - which we had to clean and it took a good while!” said Dr Boland.

“The materials had been investigated by a number of groups in the past. However, there was no consensus among researchers as to what the properties of their nanosheets were, so they were largely dismissed from investigation.”

Micas and chlorite, which had been previously studied as potential nanosheet materials akin to graphene, were deemed electrically non-conductive and chemically inert, similar to their common bulk form. Furthermore, the similarity in structure among these minerals, combined with difficulties in characterizing the nanosheets they make, contributed to their oversight.

The newly found nanomaterials exhibited a unique combination of properties, most notably tuneable electronic properties that allow for the materials to function as either an electrical conductor, semiconductor or insulator. While previously demonstrated materials like black phosphorus have also been shown to possess semiconducting and semi-metallic properties, it is less stable in air when compared to the Boland group’s materials, which exhibit long-term stability.

Most unexpectedly, the mica and chlorite nanomaterials, dubbed micene and chlorene respectively, demonstrated exceptional performances for hydrogen production, surpassing commonly utilized nanomaterials in this field. Given the UK's commitment to zero emissions targets, the development of efficient fuel sources have been denoted to be of paramount importance. The combination of cost-effectiveness and natural abundance of micas and chlorite enhances their appeal as future tools for hydrogen generation.

“Essentially, our materials could be an all-in-one source for the most basic electronic components to create future devices. Most importantly, my group’s work shows that nanomaterials with these transformative properties are all around us and can be found in our everyday lives.”

The Sussex discovery holds immense potential for revolutionizing various industries, by harnessing the unique properties of naturally occurring nanomaterials. The novel materials present an opportunity for more affordable and sustainable advancements in electronics and clean energy.

The Boland group have ongoing investigations focusing on refining and controlling their nanosheets to make more effective devices for a broader range of applied usages. Additionally, effort are underway looking at similar mineral types, aiming to expand their understanding and application of these materials.

The paper, titled ‘Exotic Electronic Properties of 2D Nanosheets Isolated from Liquid Phase Exfoliated Phyllosilicate Minerals’ (https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.202303570), was recently published in Advanced Materials.

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