A QUT researcher is mimicking the sub-microscopic structures and optical properties of natural objects, such as seashells, fish scales and fly eyes, to develop sustainable energy solutions and ways to benefit the environment.
Associate Professor Ziqi Sun has published several research papers in this field in the past 12 months, including an overview of the latest research that seeks to mimic the structural and functional properties of objects in nature by copying the nanostructure of these biological targets.
Professor Sun is a Chief Investigator with the QUT Centre for Materials Science, which has the mission to design, discover, and develop advanced functional materials to solve key technological challenges across four research themes – soft matter; hard matter; computation, prediction and modelling; and analytical methods.
Professor Sun’s research projects include developing a prototype device for removing oil spills from the ocean by learning the filtering system of fish gills, and mimicking the optical properties of abalone shells to enhance the performance of next-generation solar cells which are using titanium oxide rather than the more expensive silicon.
In July, Professor Sun published Beyond Seashells: Bioinspired 2D Photonic and Photoelectronic Devices in the journal Advanced Functional Materials. The more recent overview article Bioinspired 2D Nanomaterials for Sustainable Applications, in the journal Advance Materials, highlights how “plenty of novel materials with extraordinary properties can be created by learning from the best from natural species”.
In a project inspired by the extraordinary optical properties of seashells, Professor Sun has recently received a $330,000 Australian Research Council Discovery Project grant to study how two-dimensional structures could be used in devices such as with low-cost solar cells and rechargeable batteries.
Professor Sun said working in the bioinspired materials space meant that inspiration could be found almost anywhere.
It was during a walk through a Cairns market that he noticed jewellery made out of shells that inspired him to look at the optical properties of shells.
“Why is it so beautiful? It can probably give us some inspiration to design more optical structures,” Professor Sun said.
“Because optical properties are different to other properties – they’re not only related to materials but also related to structures.
“So let’s look at the optical properties and thinking about why it needs such beautiful colours and patterns.
“We want to mimic the optical properties and find a simple way to fabricate the structure in large scale. This is the only way we can push it to industrial applications.”
To source an abalone shell to explore its structure, he bought a plate of abalone from the seafood section of Costco and took it to the lab for detailed examination.
Professor Sun discovered the optical material on the inside of the abalone shell was the result of a nanostructure of layers, similar to sedimentary rock, with the layers alternating between hard and soft material.
He then built a material using similar layers of titanium oxide and graphene nanosheets, each of which is about one-one hundred thousandth the thickness of a piece of paper – so thin that they are referred to as two-dimensional structures.
Aside from mimicking shells to produce solar cells, his work has included mimicking the nanostructures of fly eyes to develop antifogging coatings for extreme weathers, studying fish scales to combine properties that are normally incompatible within a single material, and copying the structure of honeycomb to build better lithium ion batteries.
“We need to learn from nature, which can make the materials become different” Professor Sun said.
“By mimicking the periodic biological structures, then we can get extraordinary properties from the usual engineering materials.
“These are properties we cannot get from the conventional forms of the materials.”
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